Don't know if this is a universal phenomenon but definitely something observed locally. For very very very long time, hobbies section in my resume mentioned about music, reading etc. Why on earth do you need a section on your hobbies is never understood but since some borrowed template had it, so I kinda created "hobbies" which may (music) or may not(reading) be true :P. I never kinda really had/have a hobby though I am fierce advocate for having one. I believe it is some sort of distraction you need from your daily life, your routine, your monotony to give you glimpse of a parallel universe. Having said that I confess really having trouble in working out hobbies for own self. Here's the Standard Operating Procedure with peaks and lows.
Introduction: It is about convenience, easy (or borrowed) accessibility or getting it cheaper or free. If it involves considerable investment, count me out of it. If it requires too much effort, you are wasting your effort (on convincing me). That's why I never went for trekking. It was worst attempt by few friends of mine. It required investing on ticket trains, bus rides and then walking through shrubs with enough efforts and possibility of destroying your true solemates (shoes, i meant :p). I went for judo classes but gave up after 2 visits. One reason was to see them turning their knuckles, elbows and any visible body parts black and blue through conditioning. Secondly, there was fees and separate attire to be bought and managed. On fees part, Chris was ready to save me the investment but I wouldn't want that either. By now, I suppose you can see the pattern. Do you still need to know what happened to swimming and flying thingy for hobbies attempt?
Then how does a lazy bum gets into hobbies thingy? Well, there are two kryptonites. First, you are introduced it in the most lazy way. Like blogging, various genre of music. Second, you find a mind blowing deal and are too tempted to walk away from it. Like Cycling (Raleigh Elevation 20 in 4.5K bucks) and Photography (Sony Ericsson K300i in 5K, Fujifilm SL1000 in 11K).
Infatuation phase: In this phase, you want to try out all the options your tool provides, your own limitations, explorations and what not. Add social networking into it and you then chase benchmarks set up by your friends or your connections. The fervor is quite high during this time. Amount of energy and time spent is all time high.
Guilt phase: Now this could be externally induced or self experienced. Your infatuation phase may be adored for the initial time but after some time, people around you will be bored by your talks of it. After some more time they will start calling you back to earth. Finish this work, take care of your own self, it's not good, you are not talking to us any more and what not. If your work gets impacted by it, and if you enjoy working then the self-experienced and self-nurtured guilt will take over. If not then you will learn what friends are for! :p
Got over it phase: Just one week break from it and you will be completely over it. You won't miss your hobby any more and often question your own action for the "mad" times. If you are lucky, you will find another hobby to hitch upon. If you are eternally blessed (alike me), you will go back to relaxed/resting/hibernation mode.
Guilt reborn phase: There are two types of guilt that follows. Either you feel bad about leaving your hobby. Or you feel about spending so much money into that short lived hobby. You try to get back to the hobby. This brings to the economics part. Now the involvement is for economical reasons rather than joy which was in the Infatuation phase. If the guilt is not that strong, you keep an on-off relationship with your hobby.
Documentation phase: Subject to how invested you are in blogging, you may either write a very long blog which no one will read, or you will just add it in the resume section which (also) no one will read :P