What’s the most hurtful thing a best friend or close relative (like a cousin) said or did that made you cut them out of your life?

Someone asked a different question few hours before. But here is my version. "This person wasn't my direct relative, but we built a really close, sisterly bond. We shared everything—gossip, life’s ups and downs—and had so much fun together. She even told me I was like a sister to her, more than her real sister. But then, at a crucial point in her life, she started avoiding me and stopped sharing anything with me on purpose. That really hurt me. So, I decided to cut her off and stop talking to her. But then, she came back with some made-up stories, and I just told her to get lost"