Four samples of adults (Sample 1, N = 145; Sample 2, N = 160; Sample 3, N = 297; Sample 4 = 89 dyads, 178 individuals) completed ecological momentary assessment protocols focused on a variety of interpersonal and emotional experiences. Samples were enriched for aggressive and self-harming behavior (Sample 1), trait hostility (Sample 2), interpersonal problems (Sample 3), and personality disorder features (Sample 4). Using multilevel dynamic structural equation modeling, we investigated how emotions and interpersonal functioning operate over brief timescales in daily life. We found evidence for a vicious socioemotional cycle across all four samples, whereby negative emotions related to interpersonal conflict (i.e., perceptions of and enacting cold, antagonistic, or quarrelsome behavior; components that contribute to the interpersonal situation from the perspective of CIIT) which in turn related to increased negative emotions. Although individuals differed in the strength of this process, it was unrelated to trait negative affectivity. Viewing these results through the lens of CIIT, we discuss multiple intervention points highlighted by these dynamic results whereby the vicious cycle might be changed. (PsycInfo Database Record (c) 2024 APA, all rights reserved).