I had eight hours to chop down a tree, I'd spend six sharpening my ax. They promise to build a bridge where there is no river. The inner voice that warns us that someone may be looking. It's the worry that gets you, not the lack of sleep. Then get busy and find out how to do it.
Most people never listen.
Unfortuantely, so is losing. You don't fall off unless you stop pedaling. What is rare is the courage to follow the talent to the dark place where it leads. Excellence, then, is not an act, but a habit. It is what a man does with what happens to him.