David Letterman says the single most powerful motivating force in his life is a desire to succeed and prevail. He explains how he feels about doing “Late Show With David Letterman”:

Every night you’re trying to prove your self-worth. It’s like meeting your girlfriend’s family for the first time. You want to be the absolute best, wittiest, smartest, most charming, best-smelling version of yourself. If I can make people enjoy the experience and have a higher regard for me when I’m finished, it makes me feel like an entire person. If I’ve come short of that, I’m not happy. How things go for me every night is how I feel about myself for the next 24 hours. Because I’m not playing a character—I’m trying to give you the best version of myself.

Dotson Rader in Parade, quoted in Reader’s Digest, p. 113