Good relationships are characterized by frequent positive social interactions, such as having fun together, sharing laughs, doing kind things for one another, and expressing gratitude. In this talk, building on rapidly-emerging findings, I articulate core features of positive interpersonal processes. I then present evidence from several recent quantitative studies of people in a variety of relationships – strangers meeting for the first time, co-workers, and lovers – to illustrate the wide variety of everyday positively-valenced behaviors that help shape the best relationships. Discussion focuses on how basic research on everyday positive interpersonal processes can point toward new avenues for understanding the well-established links between good relationships and health.