I used to be in martial arts/karate which had a fairly rigorous training regimen. I suppose my first actual 'introduction' into bodybuilding would have been in 2009 when my uncle bought me a copy of MuscleMag.
It shifted my focus from just general physical fitness to body building and gaining muscle.

I was always a fan of physical fitness. Aside from the feeling you get after having a good sweat, my main motivation is the promise of a transformed body and gains in size.