Lot of kids going home from school on the school bus. Little Johnny was sitting right behind the elderly bus driver. Johnny was playing up. He was starting to irritate the driver. Johnny said in a very loud voice "If my father was a ram and my mother was a ewe, then I would have been a little lamb." No response. So Johnny then said "If my father was a bull and my mother a heifer then I would have been a calf." The bus driver had had enough. He stopped the bus and turning to Little Johnny said "If your mother was a prostitute and your father a mental twit, what would you be?" Johnny promptly replied "A bus driver!"