John and Dave, two Newfies, are building a house. John is putting on the siding. He picks up a nail and hammers it in. He picks up another nail and throws it away. He picks up a nail and hammers it in. He picks up another and throws it away…

This goes on for a while, when finally Dave comes over and asks him why he is throwing half the nails away.

John replies, “Those ones were pointed on the wrong end.”

Dave gets exasperated and says, “You idiot! Those are for the other side of the house!”