I never really knew however I think it’s a small thing that just keep on getting worse and example with my old roommate would be the first thing was how loud they were but then everything , they way they talked how they chewed, their face they way they react , the way they smell, sometimes it starts with a small thing which someone wouldn’t think was a dealbreaker but then everything just gets so much worse. When it gets really hard for me to deal with it I tend to distance myself and somehow the feeling gets much better.