"When everyone is laughing and smiling, it never fails, she either fights with her parents, complains incessantly about her husband and mother in law, and makes snide remarks to her mother and my other aunt, and she's flat out cruel to my sister, constantly judging her and putting her down, so I stay away."
There you go. She seems to just be pure nasty, and doesn't even like herself. That's sad, really. I don't know her and I pity her. As far as YOU go, YOU will be just fine!