One day this man was jumping up and down on a manhole cover screaming at the top of his lungs, "Seventeen! Seventeen!"

Intrigued by the man's insane behavior, another man walks over to him and asks why he is doing that. The first man responded, "It's a blast. You have to try it. Jump as high as you can and scream 'Seventeen!' as loud as humanly possible. You get such a rush. Try it."

Reluctantly, the second man gets on the manhole cover and barely hops and says, "Seventeen?" very timidly.

The first one says, "No, no, no. You're doing it wrong. Jump higher. Yell louder."

So, the second man begins jumping a little higher and speaking louder than normal. Finally he says, "Hey, you know, I am getting a little bit of a rush. Seventeen! Seventeen!"

The man jumps higher and higher, screaming louder and louder. The first man, once the second had jumped high enough, yanked the manhole cover out from under the second, causing him to fall down the manhole.

The first man replaced the cover and, once again, began jumping and screaming, "Eighteen! Eighteen!"