I started developing an interest in 2003, However it really wasn't until the following year that I really started learning. This website was my main source for exercise science and muscular anatomy. My Career is actually a Unix systems engineer.
I'm a big geek basically. I learn and retain large amounts of information about certain areas of interest. Or I may remember things from an article I happened to read because I saw it while doing something else and became curious, or I was looking at a wikipedia entry and got to clicking on links. I just think, "oh, whats that?" "What does that mean?" "I always wondered how that worked."
Mostly I know things about insulin resistance and obesity, because I had that problem. Any condition I have or things related to it. The human body in general, just because I have one. All the exercise and nutrition of course. Rationalism, skepticism, free thinking and related philosophy, cosmology and theoretical physics provided it doesn't require understanding long equations with Greek letters, Evolutionary Biology mainly because I'm a Dawkins fan. A lot of science stuff for the most part. Then also less serious topics like music, or movies and TV shows like Doctor Who. It's kind of sad really, you describe any classic series scene and I can tell you which episode it was off the top of my head.