The witnesses and the participants
Every history student knows about the tragedy of the commons. When farmers shared grazing land, no one had an incentive to avoid overgrazing, and without individual incentives, the commons degraded until it was useless.
We talk about this as if it's an inevitable law, a glitch in the system that prevents communities from gaining the benefits of shared resources.
Of course, that's not true.
Culture permits us to share all sorts of things without having them turn into tragedies. People are capable of standing up to the short-term profit motive, we're not powerless. We can organize and codify and protect.
It requires us to say, "please don't," even more than, "not me." Culture can be the antidote to selfishness.
In fact, it's the only thing that is.