From Warren Buffett’s 2017 letter to Berkshire Hathaway shareholders,

Though markets are generally rational, they occasionally do crazy things. Seizing the opportunities then offered does not require great intelligence, a degree in economics or a familiarity with Wall Street jargon such as alpha and beta. What investors then need instead is an ability to both disregard mob fears or enthusiasms and to focus on a few simple fundamentals. A willingness to look unimaginative for a sustained period—or even to look foolish—is also essential.