A very old couple that have been married forever are sitting by the fireside one night. Suddenly, the old woman reaches over and smacks her husband, knocking him off the armchair and onto the floor.He crawls back up and asks, "What was that for?"
She says, "For having a little willy".
He sits there quietly a moment, then smacks her, sending her flying to the other side of the room. She crawls back and asks, "What was that for?"
He replies, "For knowing there was more than one size."