A guy is sitting at home watching TV when he hears a knock on the door. He opens it up and sees a snail looking up at him. He picks up the snail and hurls it away as far and as hard as he can, closes the door and goes back to watching TV.
Three years later there is a knock on his door, he opens it up and there is the snail! The snail looks up at him and says, "What the heck was that all about??"