Being inferior to someone else can be hurtful. But what exactly happens when we found ourselves in such situations? We first address why and when upward comparison can be self-threatening and later review the effects of such threatening social comparison. We argue that two main kinds of disturbances can ensue: affective disturbances and attentional disturbances. Second, three ways to deal with self-threatening social comparison are reviewed: proactive regulation, defensive regulation, and regulation by avoidance. For each of these disturbances and regulation modes, we review empirical findings and later discuss the impact of upward comparison on performance. We conclude by going back to the very need behind the need for a positive evaluation.