The Ludic Fallacy: The mistake of neglecting the payoffs that are external to the gamble at play. For example, if you ever played boardgames, you might have noticed that only a few players play to win. Some play to have fun, and others to strengthen social bonds. Their moves might seem irrational, for they have sub-optimal payoffs inside the game. However, including the payoffs outside the game is enough to make their moves rational.