The trouble with being number one in the world - in anything - is that it takes a certain mentality to attain that position, and that is something of a driving, perfectionist attitude, so that once you do achieve number one, you don't relax and enjoy it.
It's really impossible for athletes to grow up. On the one hand, you're a child, still playing a game. But on the other hand, you're a superhuman hero that everyone dreams of being. No wonder we have such a hard time understanding who we are.