To Remember Is Painful, To Forget Is Impossible.
Tennis can be a grind and there's always the danger of going stale if you think about it too much. You can get embittered if you train too hard and have nothing else on your mind. You have to be able to relax between matches and between tournaments.
There is nothing like competition. It teaches you early in life to win and lose, and, when you lose, to put your chin out instead of dropping it.