It is widely recognized among state leaders and diplomats that personal relations play an important role in international politics. Recent work at the intersection of psychology, neuroscience, and sociology has highlighted the critical importance of face-to-face interactions in generating intention understanding and building trust. Yet, a key question remains as to why some leaders are able to ‘hit it off,’ generating a positive social bond, while other interactions ‘fall flat,’ or worse, are mired in negativity. To answer, we turn to micro-sociology – the study of everyday human interactions at the smallest scales – an approach that has theorized this question in other domains. Drawing directly from US sociologist Randall Collins, and related empirical studies on the determinants of social bonding, we develop a model of diplomatic social bonding that privileges interaction elements rather than the dispositional characteristics of the actors involved or the material environment in which the interaction takes place. We conclude with a discussion of how the study of interpersonal dyadic bonding interaction may move forward.