When dealing with people: Remember that suffering isn't optional, but negativity is ALWAYS a conscious choice. And some people just need it, depending on where they're at with themselves emotionally. They won't wish to partake in finding common ground or lifting up the collective spirit but will rather pull the situation towards dramatic outcomes to propagate their own beliefs about how rough and bad life and the world is. Most people use this negativity as an excuse to escape their own conscience and their darkness. The best skill you can teach yourself in such cases is non-participation - to walk away from a situation where arguing, debating, or winning points won't mean anything. Because the pessimist and the nihilist will always find a way to sour a situation into further negative spirals - both for you and themselves. So you're basically doing both parties a favor by walking away from the conversation - reducing your misery and theirs. And allowing them to experience the feedback loop of their own blindspots and the escapism that haunts them. The best thing you can do for an unstable personality is to leave it alone with itself - so it can see firsthand the effects of its own errors - on his own self.