When you're betting for tiles in an archery contest, you shoot with skill. When you're betting for fancy belt buckles, you worry about your aim. And when you're betting for real gold, you're a nervous wreck. Your skill is the same in all three cases - but because one prize means more to you than another, you let outside considerations weigh on your mind. He who looks too hard at the outside gets clumsy on the inside.

The Complete Works of Chuang Tzu