We propose a dynamic model of social relationships in which relational goods are the results of individual joint efforts and past attitudes towards socialising. We use a triangular finite-difference system to investigate these issues. We show the role assumed by the environment and past experience of individuals on the dynamic outcome. Particularly, we focus on the effect of aggregate effort in socialising on equilibrium system properties. We show that the system may converge to an equilibrium with a low level of socialising not only in environments relatively poor of relational goods but also in environments with excessive investment in relational goods. Low-socialising traps may be the result of a congestion phenomenon in social relationships. If a relation requires too much effort, individuals may prefer to replace it with other less demanding activities. We analyse a few policy corrections to avoid socialising traps.