Two hermits lived in a cave far from civilization. One day a little dog ran past the entrance to the cave.
Six months later one hermit said to the other one, "That was a cute little black dog."
One year later the other hermit said, "It wasn't a black dog; it was a white one."
Eight months later the first hermit jumped up and exclaimed, "If we're going to have this constant bickering, I'm leaving."