This seems like the kind of question that would really very person-to-person. For me living is being happy, enjoying life, being active in your life, feeling connection to other beings in the world, and making the best of opportunities in your life. Existence is more just being a living being (or even non-living being) and existing in a state of "being," but without really experiencing all life has to offer.
day 1: hopes, dreams, and plans for the next 365 days with a picture of yourself
day 2: something that’s illegal but you think it should be legal
day 3: what you think your reason for being here is
day 4: how you think your life would change if you achieved your dream
day 5: something you would change about the world
day 6: something you would like to change about yourself
day 7: a show or a movie that has changed you, and how
day 8: things that make you sad
day 9: things that make you happy
day 10: what you think when you hear the words “be yourself”
day 11: the worst advice you’ve ever heard, or ever been given
day 12: the best advice you’ve ever heard, or ever been given
day 13: your favorite quote
day 14: write about something you believe in, anything at all
day 15: a song that makes you cry and why
day 16: someone you trust
day 17: your idol and why you look up to them
day 18: why you made your blog, why you still have it
day 19: your thoughts on your family
day 20: what you think makes someone beautiful
day 21: everything you wish for in a significant other
day 22: how you judge intelligence
day 23: a month/year of your life when you were happiest and why
day 24: your favorite 10 people right now and why
day 25: a friend you have lost that you’re better off without/one you wish you had back
day 26: 5 things you’re looking forward to
day 27: a person you wished lived closer and why
day 28: something you makes you really angry
day 29: a date you’d love for someone to take you on
day 30: 5 favorite girls names, 5 favorite boys names
day 31: a bit about your social life outside of tumblr
day 32: whether you’d rather marry someone who’s rich but ugly, or poor but attractive
day 33: someone who really hurt you
day 34: your horoscope for today and whether you think it’s accurate
day 35: words you live by, why do you like them
day 36: what you think about your friends
day 37: who are you?
day 38: thoughts on your generation
day 39: why you think you’ve learned more from the good or the bad
day 40: what are features you get complimented on a lot
day 41: write a letter to yourself stating all the things you love about yourself
day 42: your best friend just died, what is your reaction
day 43: is it possible to lie without saying a word
day 44: when is it time to stop calculating risk and rewards, and just do what you know is right
day 45: when was the last time you tried something new
day 46: what makes you smile
day 47: is the truth always good to hear, why or why not
day 48: your life story in three words
day 49: are you a lover or a fighter
day 50: why you are doing this challenge
day 51: describe your future wedding
day 52: what is the most inspirational thing you’ve ever heard
day 52: if you didn’t have an age, how old would you think you were
day 53: your day, in great detail
day 54: your definition of love
day 55: a passage from a book that has touched you
day 56: something you did as a child that other people remember you for
day 57: what is your definition of happiness
day 58: places you want to visit, and why
day 59: one person you can tell everything to
day 60: a youtube video you absolutely love and describe why
day 61: one of your most prized possessions
day 62: describe your best friend completely
day 63: your views upon gay marriage
day 64: your best friend is in a car accident and you two got into a fight an hour before, what do you do?
day 65: one random fact about yourself
day 66: if you could switch lives with someone for a day, who would it be
day 67: how you found out about tumblr, and why you made one
day 68: the best concert you have been to
day 69: powerful song lyrics you love
day 70: a celebrity you don’t necessarily enjoy, and why
day 71: differences between you and your best friend
day 72: list of everything you ate today
day 73: a movie you cried in
day 74: how would you describe your style of clothing
day 75: what is one of the best dreams you have ever had
day 76: how do you feel about going green
day 77: what gives you every day inspiration
day 78: would you rather people be honest with you, even if it’s something not good, or lie to you to make you feel good
day 79: why do you feel as though people judge others
day 80: one of your favorite childhood memories
day 81: what is your biggest fear
day 82: would you break the law to save a loved one
day 83: if you had to teach something, what would you teach
day 84: do you think crying is a sign of weakness or strength
day 85: if you had the opportunity to get a message across to a large group of people, what would your message be
day 86: what is the difference between living and existing
day 87: what are your views upon sex before marriage
day 88: does money equal happiness
day 89: are you self aware
day 90: write a letter to one of your close friends
day 91: name a book you read in school that wasn’t entirely awful
day 92: what have you learned just from attending your school
day 93: what about the opposite sex can you not understand
day 94: do you keep your thoughts to yourself
day 95: describe the weather occurring right now
day 96: what do you love the most about your grandparents
day 97: something you’ve always wondered
day 98: what would be the hardest and most fearful thing you would ever have to face in your lifetime
day 99: do you think it’s better to have a few close best friends or to have a lot of acquaintances
day 100: what is the best thing about being your age
day 101: would you like to travel abroad to learn about new things throughout the world
day 102: life lessons you’ve learned throughout life
day 103: do you believe in love at first sight
day 104: three words you cant go a day without using
day 105: describe your favorite place in the world
day 106: someone you judged by the first impression
day 107: the friendliest personn you knew for only one day
day 108: is it easier to forgive or forget
day 109: if you were a super hero, what kind of powers would you have
day 110: something that makes you happy
day 111: do you wish upon 11:11 even if it may not come true
day 112: what is the most important part in a relationship, do you think
day 113: do you believe that if you want something enough you’ll get it
day 114: do you like when people are protective over you
day 115: is it possible to be single and happy
day 116: one guy who means a lot to you
day 117: if you were to get a tattoo, what would it look like
day 118: what people in your life inspire you the most
day 119: something you hope you never have to do
day 120: what is your zodiac sign and what do you think it means
day 121: what do you think about stereotypes
day 122: which activities make you lose track of time
day 123: do you believe teenagers can fall in love
day 124: have you ever had feelings for someone who was seeing someone else
day 125: have you ever gone out of your way to make someone happy
day 126: have you ever been betrayed by someone you trusted
day 127: do you believe in second chances
day 128: what is your life’s purpose
day 129: favorite month of the year and why
day 130: if you were deserted on an island, what would you bring
day 131: what do you worry about
day 132: do you believe ex’s can be friends
day 133: if you had to choose between a million dollars or to be able to change a regret, what would you do
day 134: do you have a reason to smile right now
day 135: is change a good thing
day 136: if you were 12 and looked at yourself in the future, would you be happy
day 137: one of your wildest dreams
day 138: one of the nicest things anyone has said to you
day 139: something you can’t wait for
day 140: how do you feel about people disrespecting their parents
day 141: someone who fascinates you
day 142: how have you changed in the past 2 years
day 143: how important you think education is
day 144: are you planning on having children one day
day 145: is it easy to trust others
day 146: is there someone that makes you happy everytime you see them
day 147: what do you think about ignorant people
day 148: do you think more about the past, present, or future
day 149: would you rather love one person or have many short relationships
day 150: how is your heart lately
day 151: would you move to a different country to be with the one you love
day 152: what is one step of action you would take to change the world
day 153: do you think the hardest thing is sometimes the easiest thing
day 154: a moment you felt most satisfied in your life
day 155: what is one achievement you are proud of
day 156: what is a tv show you enjoy the most
day 157: do you like to give or receive
day 158: would you give up all of your presents one christmas time to help others from other countries
day 159: what is one thing you love about photography
day 160: do you go by live, laugh, love
day 161: why is it so much easier being a child, than an adult
day 162: highs and lows of this month
day 163: where is one place you would love to visit
day 164: one thing many people don’t know about you
day 165: favorite type of music
day 166: have you ever had a teacher that changed your life
day 167: funniest movie you have ever seen
day 168: how do you feel about cyber bullying
day 169: what is your life motto
day 170: what is something you notice throughout high school
day 171: one famous guy you would marry in an instance
day 172: what kind of person attracts you
day 173: is there something you laugh at everytime it happens
day 174: how do you think you’re going to act like in 10 years
day 175: songs you listen to when you’re happy
day 176: do you enjoy cooking
day 177: something you’re proud of in the past few days
day 178: a goal you have this weekday
179: how do you feel about discrimination
day 180: what is the most inspiring book you have read181: how did you spend your last birthday?
day 182. why do you think people are so addicted to facebook/tumblr?
day 183: you are told you have one week left to live, how do you spend it?
184: when you think of your best friend, what is your first memory? how did you meet them, explain him/her.
185: where will you be in ten years?
186: have you ever made a time capsule? If yes, with who, do you remember what you put inside? If not, what would you put inside if you had to put something in right now?
187: post a picture of yourself, taken today, and five random facts about yourself.
188: what are you always carrying around with you?
189: list everything you like about yourself, and explain why. What makes you unique?
190: put your ipod or mp3 player on shuffle and list the first ten songs/artists. How did you find the music?
191: are you excited for anything right now?
192: summer or winter? why?
193: what are you doing for the next big holiday. (i.e. Christmas, Hanukkah, Thanksgiving, Easter, Passover..)
194: what did you do today?
195: have you ever had braces/will you ever need braces?
196: what is one thing you regret doing?
197: do you have a set out path for your future yet?
198: a picture taken over ten years ago
199: what is the last book you read, why did you read it?
200: whatever suits your fancy.( a picture, random facts, what you did today, your plans for tomorrow)
201: what are your plans for tomorrow.
202: what did you do last saturday?
203: what is the last thing you had to save your money for?
204: do you have a job, if so, where?
205: do you believe in love at first sight? why or why not?
206: what’s your favorite band?
207: have you ever cried in a movie? which?
208: tell us about your family.
209: what do you remember most about last winter?
210: in a nutshell, what is your daily routine?
211: a picture of you and your best friend
212: one person you know you can trust?
213: the person closest to your heart.. how do you know them?
214: what are your feelings on gay marriage?
215: a letter to your crush
216: list of some of your favorite tumblrs
217: a letter to someone who you used to be close to
218 : a letter to someone you judged by first impression
219: a talent you have
220:a picture that makes you smile
221:a photography picture taken by you. (credit it!)
222: what are you craving right now?
223: bad habits of yours.
224: a letter to your eight year old self.
what is the most inspirational thing you have ever heard
next present holiday wish list
227: a letter to the reflection in the mirror
228: list ten people you would die for
229:write a letter to the person you’re closest to
230: what is your favorite memory from before the school age.
231: what were your thoughts enter pre-school, kindergarten, middle school, and high school
232: how was your last year in school? which grade level was it?
232: list the movies you’ll never get sick of watching
233: what is the most quotable movie.. list a few of your favorite quotes?
234: favorite song as a ten year old?
235: if your six year old self looked at you now, what would their reaction be?
236: what was your most memorable summer
237: who from full house do you relate to most?
238: who/what can’t you live without?
239: have you changed in the past 200 days?
240: what does your name mean according to urban dictionary? were you named after anyone in your family, or does your name mean something special to your parents?
241: what name would your parents have named you if you were the opposite sex? did they have a list of names for you?
242: 10 most significant events in your life
243: what is the last thing you baked?
244: a picture taken recently
245: what is the compliment you get most, what is the compliment you give most?
246: who are you?
247: your opinion on drinking/drugs
248: who do you text most
249: if you died tomorrow.. would you want to tell anyone anything?
250: write a short love story
251: what inspires you to write?
252: list five things that make you happy
253: list five things that make you sad
254: list your five favorite foods
255: list your five favorite drinks
256: list five things you want to say to ten different people at this moment
257: list five good things about your life
258: list five bad things about your life
259: list your family members and how they help you daily
260: list your five favorite songs
261: list what you did/plan to do today
262: list your favorite stores
263: list how you did your make up today
264: how are you wearing your hair
265: post a picture of your outfit, or explain it
266: an old song you still like
267: when you’ve had a terrible day, how do you deal with it?
268: an overused saying?
269:how are you similar to and different from the majority of Tumblr users?
270: what would your dream house/apartment/castle/tree house/loft/bungalow/etc. look like?
271: who makes your happier than anyone else?
272: what was the worst thing to happen to you in middle school?
273: seven things that cross your mind a lot.
274: six things you love
275: five songs you like.
276: four things you wish you could say, but might never.
277: three things you miss
278: two things you want.
279: one story of a memory you have.
280: what was the last movie you watched, write about it
281: someone you would switch lives with for a day and why
282: if you were stranded on an Island, who would be with you and which limited 10 items would you two have?
283: describe your perfect date
284: write the differences between you and your best friend
285: what got you into this challenge?
286: a picture of what you wore today
287: a silly picture of you/ you & your friends
288: last post you made on Tumblr that doesn’t involve a challenge?
289: write a letter to your followers
290: a video you would usually watch on Youtube
291: what did you eat today?
292: recommend a few Tumblr’s and write why you recommended them.
293: when you look outside step outside your front door of the house, what do you see?
294: something that inspires you
295: things you’re looking forward to next week -month
296: create a collage of your pictures you take in 1 day and post them up.
297: when did you start wearing makeup?
298: do you like to dress up or dress down for school
299: who’s on the left of your locker who’s on the right? do you like them?
300: your celebrity crush
301: who is your favorite actor/actress and why?
302: post a picture of your makeup from today!
303: last time you were sick, what did you have?
304: What is your favorite kind of soup?
305: which grade was your favorite? why?
306: what are the most distinct memories from preschool age and younger?
307: what are the memories you have when you think of kindergarten?
308: what are the memories you have from first grade?
309: what are the memories you have from second grade?
340: what are the memories you have from third grade?
341: what are the memories you have from forth grade?
342: what are the memories you have from fifth grade?
343: the last person you texted- how do you know them?
344: post a picture of yourself today
345: write a letter to your best friend
346: what are your favorite type of shoes? why?
347: are you getting bored of this challenge?
348: what’s the most embarrassing thing you’ve done lately?
349: what’s the way to win your heart?
350: do you have any hard, life-changing choices to make, anytime soon?
351: are you addicted to facebook?
352: do you know anyone with an outie belly button? who?
353: what quote do you live by?
354: last time you cried, why was it?
355: honestly, do you know all the words to your countries national anthem?
356: what is your dream job?
357: as a kid did you want to be a ninja turtle and/or power ranger? which color?
358: are you as addicted to tumblr as you were a year ago?
359: describe what you normally do on a weekly basis. A little bit about your social life outside of the internet.
360: a picture of what you wore today
361: If you won the lottery, honestly, how would you spend the money?
362: what is the biggest lie you’ve ever told. why’d you tell it?
363: do you know what your first post on tumblr was?
364: have you changed much in the past year?
365: look back to your first post of this challenge, asking ‘Post a picture of yourself and tell us your hopes, dreams and plans for the next 365 days’ did you achieve any of these goals? And post a picture. :) thanks for completing the challenge