The real sting in Buffett's observation lies not in celebrating discipline—everyone admires that—but in recognizing that saying yes to good things is precisely what derails excellence. Most ambitious people suffer from a surplus of worthwhile opportunities, not a shortage; the limiting factor isn't willpower to refuse the mediocre, but courage to reject the genuinely appealing. A talented programmer might turn down lucrative consulting gigs or speaking invitations that would inflate her résumé, not because they're beneath her, but because they splinter focus from the one software product that could define her career. The hardest "no" is always to the next right thing, not to obvious distractions.