It's a funny thing, a man can make a promise to his god, break it five minutes later and never think about it. With an idle shrug of his shoulders a man can break solemn promises to his mother, wife or sweetheart and except for a slight momentary twinge of conscience, he still won't be bothered very much. But if a man ever breaks a promise to himself he disintegrates. His entire personality and character crumble into tiny pieces and he is never the same man again.
Monte Hellman 1974