Two Canadians and an American are sitting on top of a mall when the nerdier of the Canadians turns to the american and says, "I bet you fifty dollars I can jump off of this building, hit that umbrella on the sidewalk and bounce back up unharmed."

the American thinks about it and says "sure"

So the guy walks over to the edge, jumps off, hits the umbrella and bounces back up.

The American gives him the fifty dollars and says "Wow, I bet $100 I can do it too!"

So he jumps off of the building, hits the umbrella, falls through it, hits the ground and dies instantly.

the other Canadian turns to the nerdier one and says "You know Superman, you can be a real jackass sometimes..."