Positive illusions, though often beneficial (Taylor & Brown, 1988), can diminish the pleasure of outcomes. This prediction follows from decision affect theory. We investigated this prediction by measuring the confidence that recreational basketball players felt while making shots and the pleasure they felt with subsequent outcomes. Results showed that most players were overconfident. Those who were more overconfident tended to experience less enjoyment with their outcomes. Using individual parameter estimates from decision affect theory, we estimated how each player would have felt if their self assessments had been accurate. For the vast majority, better calibration would have led to greater pleasure. In a second study, we randomly assigned players to a debiasing treatment condition or a control condition. Relative to the control players, debiased players were better calibrated and derived greater average pleasure from the task. Copyright © 2004 John Wiley & Sons, Ltd.