The Snail
A guy goes to his front door to pick up his newspaper. He opens the door, bends down to pick it up, and notices there is a small snail sitting next to the newspaper, just as peaceful as can be. Without even thinking, the guy picks up the snail and hurls him into the bushes.
Two years later there's a knock at the guy's door. He goes to the door, opens it and looks around, but no one is there. So he closes the door and walks back inside. Seconds later, there's another knock. He opens the door again, looks down and there's the snail.
The snail looks up at him, and says "Hey! What was that all about?"