The essence of mathematics lies in its freedom.

If you plan on being anything less than you are capable of being, you will probably be unhappy all the days of your life.

The mind is the most important thing in tennis.

Here's where it makes the most sense. You need it so you don't forget. Forget that there are palace in the world that aren't made out of stone That there's a---there's a---there's something inside that's yours, that they can't touch.