I think you're in for some good replies.
Looking back I didn't get the bug till I started getting some help from a bodybuilder friend of mine way back in the day. I was mostly going to the gym just to add some "size" while I trained for my military pt tests. And of course I grew up with Arnold, the rockies, Rambo's and every other larger then life actor coupled with my dad and me watching pro wrestling growing up. To me those guys were the definition. Larger then life and strong as hell! Of course the more time I spent around bodybuilders the more I started to understand HOW people got to be larger then life. Kind of my own "bigger, faster, stronger" moment. Realistically what kept me from going full on competitive bodybuilder was that I don't like that judges can arbitrarily decide who has the best physic, there has always been this notion in my head that they don't really quantify with any kind of actually measurements or anything. Mind you I do have respect for judging as thats hard to really pick one person over another in that situation, but still was never something I liked.

Of course after years of following basic body building routines I eventually stumbled into powerlifting. While I would say that sometime judging on squats can be less strict then I like for the most part its who moves the most weight, in a certain class, that wins. And I like that. Also I was starting to loose some focus in the gym, but being able to focus on improving my lifts, and refine my technique keeps me focused.

Even so I still find myself eyeing the next weight class up, or looking in the mirror thinking which muscles may be lagging, or just flat out wishing I was stronger. I say that fixation is a good thing though. That drive and passion pushes us to try and be more then what we were. Be it those 10lbs on a max attempt, or 10lbs of lean mass your working to build, then reveal to the world.. the passion makes us better.