Buffett's guide to the psychological pitfalls that sabotage investors

Warren Buffett described a set of internal adversaries—fear, greed, envy, impatience, and the pull of the crowd—that repeatedly undermine investors. He labeled fear and greed as "super-contagious diseases" in his 1986 letter, emphasizing that their timing cannot be predicted, only the response can be managed. Drawing on the 2008 crisis and the dot-com era, Buffett showed how panic or euphoria can tempt even seasoned investors to abandon solid valuations.

He warned against impatience and the urge to act, urging a disciplined restraint likened to a 20-punch-card that forces each decision to feel weighty. Envy, he noted, can drive investors to chase risky bets simply to keep up with peers, while herd behavior can lead rational people to follow irrational market trends. Buffett’s broader counsel is to stay within a clear circle of competence, admit what one does not know, and detach from popular opinion, thereby protecting long-term performance.