ABSTRACT This paper examines an emerging optimal condition for informal public social interaction, which has not yet been fully accepted or theorized in sociology and urban design. The condition in question is human congestion and is the target of current sociological and urban design critiques. This paper employs empirical material from a case study which illustrates and problematises this condition and its critiques. It uses Goffman’s “Interaction Order” as a theoretical and methodological framework, combining observational, interviewing, non-verbal communication, and spatial analysis methods, to examine the social interactional potential of a range of new public spaces designed with congestion in mind. In doing so, it problematises the critiques of human congestion demonstrating that informal public social interaction under such condition occurs more than it is necessary and that the spaces where it occurs can become valuable social spaces for a wide range of users.