[Spenner]

Holy shit this thread is evolving into the a perfect epitome of the theme of the title. We're all turning on one another.

For my contribution, I think you should evaluate people on an individual basis, and see if there is a mutual acceptance of one another, comparative empathy, and then decide if you want to make sacrifices of any sort, or start on any tit-for-tat kind of interaction. By default, have a bit of vigilance but always understand the underlying potential for people to be part of reciprocal altruism, or straight up feeling good about being around other people who have the common grounds of being human, and living a confusing but interesting life.