What's the Point of a Good Prank?

A good prank does not have much potential for really exposing someone and humiliating them at a level that could permanently change their life. What are you hoping to accomplish with the thing? Who gets the laugh? Who's the butt of the joke? How long are they on the hook? Are we going to tell them that it happened or are we just going to let the embarrassment sit? It's all considerations.