Health is the same way. As long as one enjoys good health one never thinks what a privilege, what a blessing it is. It is afterwards, when it no longer exists, that one begins to realize, "What have I lost!" Life, as Omar Khayyam says, is a wine press, and every good thing that comes, comes just like a wine. It is a reward; but this reward may intoxicate a person, and a person may forget to appreciate it and to be grateful for it. With the mere fact of his forgetting that privilege, the reward is taken away from him, and then he begins to value it and appreciate it, when he is empty-handed.