...He's a dick.
I didn't quite believe it at the time, but a while ago I'd heard that Superman was originally conceived to be more of a villain than a good guy. I mean, if he was evil, what would have stopped him from destroying the world, or doing anything else he wanted for that matter? But no, he wasn't evil, he was just a jerk.
Later, his image was changed to make him into the mild mannered defender of truth, justice, and the American way that we all know and love.
But he was really a dick.