ABSTRACT It is common in studies of interpersonal characteristics to examine personality variables as static predictors. Yet in recent years it has also become possible to examine personality and related interpersonal processes as they unfold over time in association with event specific cues. The present article reviews research that (1) identifies behaviors that reflect the occurrence of hostile-irritable-quarrelsome traits in daily life, (2) demonstrates both the stability and within-person variability of these behaviors over time, (3) documents event-level interpersonal cues that are systematically associated with within-person variation in quarrelsome behavior, and (4) describes how dispositional level agreeableness and irritability moderate the associations of event-level cues with quarrelsome behavior. The influence of the neurotransmitter serotonin on quarrelsome behavior is also considered. The studies indicate that quarrelsome individuals have reduced affective reactivity to engaging in quarrelsome behavior, increased behavioral reactivity to perceptions of quarrelsomeness in others, and greater responsiveness to change in serotonin levels.