What's one thing about someone you know that you absolutely cannot stand?

My suitemate has this friend over all the time, who is constantly laughing. It would be one thing if she had a pleasant, infectious laugh…. but no. She sounds like a goddamned hell-beast. It’s literally the worst sound I’ve ever heard. My stomach wrenches up every time I hear it wreaking havoc on the airwaves. I don’t know how anyone can stand to be around her. I’m in an entirely different room and I want to shoot myself. Gahhhh. Anyone able to relate?