Counterfactual thinking has been defined as images of alternative scenarios to past events (Roese, 1994), with counterfactual thinking about better alternatives leading to negative emotions and, when excessive, forming a risk factor for depression and poor coping with stressful life events (e.g. Davis, Lehman, Wortman, Cohen Silver, & Thompson, 1995). In three studies we investigated whether the ... [Show full abstract] self-regulation strategy of mental contrasting helps to regulate negative emotions resulting from counterfactual images or fantasies. Positive images or fantasies about better alternatives to past events, similarly to positive fantasies about desired future events, fail to integrate the present reality. The self-regulation strategy of mental contrasting complements positive future fantasies with the present reality leading to disengagement from future fantasies when expectations of success are low (review by Oettingen, 2012). In three experimental studies we hypothesized and observed that mental contrasting of positive fantasies about alternatives to past events disengages people from counterfactual fantasies when expectations of realizing those fantasies are low.