I had in the past lived in flat/house shares for quite a few years.
My worst by far was a girl I was in halls of residence during my postgrad year at uni. It was a 5 room flat in a big halls building, and the room right next to mine was occupied by a girl whose boyfriend lived on the same floor (flats were not mixed sex, so they could not live in the same flat).
For whatever reason, they never went to his flat for anything, but kind of lived in ours, both of them. They were both extremely loud and expressive, talked like if they were shouting. Also leading an owl lifestyle, they would eat late and stay up until early hours of the morning, hangind around between her room and the kitchen, banging the door every time they entered/left the room making my whole wall shake. She didnt have to wake up until 10/11 am, so had plenty of sleep.There were no earplugs that could cancel the noise and vibrations, and I had to also hear the alarm clock in the morning. My degree was super intense and I had to be up every morning very early, and worked until late and the whole year I hardly could get any sleep, it was so miserable I don't know how I actually made it through the year on 4 hours of sleep a night (if I was lucky).
Funnily enough when the exam session was on, she banged on my wall when I was skyping my family at 8PM as she 'had to study,' the only two weeks of peace I had between September and July. I spoke to her a few times, to no avail, she was actually louder out of spite.
The other girls in the flat did not experience that as none shared a wall with her, so they never got how stressful it was.
I had had great experience of living in halls up until then, but that year exhausted me.