[nayroclade]

Humans do great in groups until they get bigger than the size of a larger hunter-gatherer tribe, say more than a few dozen individuals. Basically, the point at which it becomes impossible for everyone to know everyone else, and you need to replace informal, personal organisation with formalised and impersonal structures.

Humans are not rats, but nor do we really behave like other primates. We have evolved to co-operate socially and we do it very, very well, including (and perhaps especially) in resource-constrained environments. And we even engage in self-domestication to weed out individuals who attempt to dominate or cheat in such situations.

But the problem with modern society is it throws all of that evolved ability out of the window. We are attempting to learn how to co-exist and thrive while living in cities of millions of strangers, while living lifestyles their bear no relation at all to traditional human life. In a way, it's a miracle that we do as well as we do.