That people are fundamentally benevolent to one another. Obviously it can be trained out of you by circumstance, overcome by self-interest, and mental illness is a thing, but I think people innately care for one another. It's why dehumanization is the first step to committing atrocities.
But if someone offered proof that I'm wrong that might be the least surprising thing that happened all week. And if I'm wrong, the evil-doers are sub-human and should be culled without mercy until I am right.