Every decision requires a prediction, both about what will happen and about how the decider will about what happens. Thus, decisions require what is known as . This chapter reviews evidence that people systematically mispredict the way experiences will feel. First, predictions about the future are often based on memories of the past, but memories of the past are often inaccurate. Second, people predict that the affective quality of experiences will last, thereby neglecting the widespread phenomenon of adaptation. Third, in anticipating an experience, people focus on aspects of their lives that will be changed by the experience and ignore aspects of their lives that will be unaffected. Fourth, decisions are profoundly affected by the choice context, even though the choice context will no longer be relevant when the chosen object is actually experienced. Each of these affective forecasting “errors” can lead people to mispredict satisfaction with decisions.