Well, I think the key is to pay attention to individuals who say "I feel this way and it's YOUR FAULT". This can be a red flag that you may be dealing with a person that blames outside input on how they feel. That's not a person who is willing to own their own feelings and instead chooses to blame their feelings on others.

This is what I kept dealing with when it came to my older sister and she is very disordered and engages in all kinds of cognitive distortions and likes to create her OWN narrative which isn't based on truth and reality. My sister is very prone to blowing up in rages and doesn't care who she rages in front of either. There are times where the best thing to do is completely disconnect when a person begins to show the red flags and you basically have to tip toe around them constantly.