Why do people experience anger? Most of our knowledge on anger-triggering events is based on the study of reactions at a single time point in a person's life. Little research has examined how people experience anger in their daily life over time. In this study, we conducted a comprehensive examination of the situational determinants of anger over the course of 3 weeks. Using daily diary methodology, people (N = 173; 2,342 anger episodes) reported their most intense daily anger and, with an open-ended format, described the trigger. Participants also answered questions on anger intensity, control, and regulatory strategies, along with baseline personality trait measures. Using an iterative coding system, five anger trigger categories emerged: other people, psychological and physical distress, intrapersonal demands, environment, and diffuse/undifferentiated/unknown. Compared with other triggers, when anger was provoked by other people or when the source was unknown, there was a stronger positive association with anger intensity and lack of control. Personality traits (i.e., anger, mindfulness, psychological need satisfaction, the Big Five) showed few links to the experience and regulation of daily anger. Although aversive events often spur anger, the correlates and consequences of anger differ depending on the source of aversion; personality traits offer minimal value in predicting anger in daily life.