Today, I read a story in which a father taught a very good lesson to his son, through the wise saying. He crack a joke, on which his son began to laugh. He repeated the same joke again, this time boy also laughed, but not in position he did for the first time. His father repeated the joke again and again, until the boy stopped to laugh. As the joke was not more interesting to him. When he asked his father the reason to repeat the same joke, he said, "When you can't laugh at the same joke again, so why to shed tears for the same reason every day." This made the boy to understand his father wisdom.