I always saw the tragedy of the commons as very similar to the prisonner's dilemna: the optimal strategy for each individual leads a globally unoptimal situation.
A real-life exemple: elections. Your vote is not going to tip the scale, and so voting is a waste of time. Except that if (mostly) everyone does this, it only leaves a handful of idiots / fanatics / paid voters to decide on the issue.
Interestingly, most people get very upset when you suggest that voting is a waste of time. More understandably, most people condemn the idiot in the tragedy of the commons. So there seems to be a strong "sense of the commons".