Learning Human Nature will give you skills to protect you from harm and to empower you for success in life with other humans.
One skill that can help you is recognizing when someone is using Splitting. Splitting is a defense mechanism. Splitting is when someone calls you good OR bad instead of seeing you as good AND bad. The reality is, no-one is all good and no-one is all bad, but when they call you all good or all bad, this is a problem. Saying that is equivalent to saying you serve my ego (you agree with me and therefore are good) or you challenge my existence (you disagree with me and therefore are bad).
When you meet someone like this, know that this means they are insecure. Treat them like a 7 year old and calm them down like you would a child. Then try to talk to them after they are calm, or just let go and move on.