Snail craws into a bar, crawls up to the barman and asks for a pint. The landlord plucks the snail from the bar, walks to the front door and throws the snail as far as he can.
Three months later in the middle of the night there is a knock at the door. The landlord opens the door and sees no one, but looking down sees a snail on the doormat.
"What did you do that for?" asks the snail.