"Doubt is most often the source of our powerlessness. To doubt is to be faithless, to be without hope or belief. When we doubt, our self-talk sounds like this: 'I don't think I can. I don't think I will.'... To doubt is to have faith in the worst possible outcome. It is to believe in the perverseness of the universe, that even if I do well, something I don't know about will get in the way, sabotage me, or get me in the end."