I started competing to see if I could be great at it. That's pretty much the only reason I like doing stuff...to prove to myself and everyone around me that I'm great at it. Otherwise, what's the point? The only other reason I do things is because it's memorable or rare or unique, which although not great per se, has its own merits.
Turns out, I'm not really that great at it, judging by how far along I was able to get in the ranks.
Now, I do it because at my age, it's very unique. Not a lot of guys in my circle of friends doing it (most working a desk job, are normal-shaped for men in business, and raising kids), so when I cut down for a show, folks my age are genuinely impressed, or jealous, or freaked out, or inquisitive, or grossed out, but rarely are they indifferent. Thus, it's memorable. Maybe not always good, maybe not always bad, but at least they remembered the weird guy they met who starved and lifted weights. Better than being a forgettable nobody. Also, my kids are young enough to still think it's kind of neat (they'll learn to think it's gay in about 10 years or so, so I have a limited time frame to do it before it becomes embarassing to my kids. Then I'll have to give it up. I don't mind humiliating my wife though...she married me so she has to put up with my crap, just like I do hers).