What's with our desire to make our muscles as big as possible? Sure, there's something evolutionary about wanting to be fast and fit so you can hunt better, but cavemen didn't look like Mike Tyson. No, to my knowledge people didn't get as huge as The Rock until the advent of gyms and protein powder. So what made us want to look like that? A desire to not fit through doorways? To provide your children with a human jungle gym? To get so big that you can crush your enemies?
Honestly, I think it has a lot to do with Arnold Schwarzenegger in Terminator. He was huge, and he was awesome, and he had epic one-liners, so dudes wanted to be like him. Which I think is a noble effort. But gym dudes need to work on their epic one-liners. Less, "lightweight, brother" and more "Hasta la vista, baby" That's the world I want to live in.