This stems off of Jimmy's post since I was thinking about it myself earlier today. I was gonna comment but decided it was more worthy of something I'd want to read later, I don't care if y'all do.
People view the world in two different ways. By which I mean there are two main categories of thinkers as to the reason each of us was put on this earth. One side views the world as this being that is constant, it will always be here. It changes, yes, but the change is on such a scale that the individual lives aren't going to make any sort of impact on its natural progression. So individually, where does that leave us? Well, as I take this side, I can explain that each person has their goals. I personally will be content with my life if I come to the end of it and I can look back and say, yes, I had a good life. My definition of a good life is probably centered around happiness, either mine or other peoples should they not coincide. Other people might be content if they can surround themselves with family or friends. I want to remember the actions, the thoughts, the intangible stuff that seems to matter all the more but its inherent evanescence.
The other side has its merits, too. And I used to be of this persuasion. This side views the world as a changing being that each person helps to mold in someway. They measure their accomplishments by how much good they did, how much effect it had. No matter how small the effect, however, people still interact and affect each person they come in contact with. Ever seen 13 conversations about one thing? I'm sorta giving away the ending, so
the girl sees a guy on the subway and he smiles at her. No reason at all, he just smiled. And that one thing made her stop, hit her head-on and caused her to change her outlook on life and so she doesn't kill herself. The point is that every action, no matter how small, has some impact that may not even be related to the size of that action. Thusly each person affects the world and you would be content with your life if you could look back and feel like you made a difference. That difference could have been saving millions of lives or it could have been teaching 100 kids to read. The measurement is up to you and you can do with it as you wish.
As I said, I'm more of the first persuasion, but I know that I make a difference as well. The difference in thinking is that that difference is not what matters to me. The end result is not what I look for. I look for the journey, the process one goes through to get to that conclusion, that's what counts for me. I think I've known that my whole life but only in the past year or so has it become clear to me.