This article addresses the notion of limit based on sociological-philosophical reflections made based on field work carried out in mass public transport. Its purpose is to contribute to the conceptualization of the limit as a category of analysis present in various debates in the social sciences. The theory of symbolic interactionism and the approaches of the philosopher Eugenio Trías, served as references for the study and interpretation of face-to-face encounters between users, this being the constitutive condition of the research, since the object of study is also the category of analysis. To capture the everyday presentation that people make when facing each other, systematic observations were conducted inside mass transit units and targeted conversations were held with users.
