Last year I got a bit of an amateur obsession with the concept of "us vs them." I first read about it in Sapolsky's Behave, I think.

It caught me off guard that the hormone that produces the "us vs them" feeling is dopamine. The brain releases it to strengthen social bonds and group identity, which makes us more distant from anyone who doesn't share the values and beliefs of our particular groups.

The more you feel part of your group (which is psychologically essential if you don't wanna turn into an adult-diapered quarantined subreddit-browsing wacko), the more you are wired to feel this sense of otherness that separates you from everyone else.

So basically, we can have nice things. As long as everyone else's suck.