My only 2 roommate experiences were imposed on me, in 2-bed dorm rooms: one was mandatory for college freshmen, and the other in Army enlisted barracks (excluding my initial training, when we slept in larger multi-bed bays, as often portrayed in movies). While I prefer to sleep with my lover, in the same bed when possible, when there's no romantic interest in the guy I find the loss of privacy a bit uncomfortable.
College dorm: my roommate was taking Army ROTC, which I had declined, first year (1967) that freshman males had the option on that campus, but about half still did. At 18 I hated the Army, yet ironically 15 years later I was an ROTC instructor myself as a Major.
So anyway, this guy would spend hours spit-shining his boots & shoes, and cleaning his metal uniform insignia with Brasso, which made me nauseated from the smell, dirty cleaning rags all over the floor and our dressing counter. When he came back from outdoor training his soaked fatigues would sometimes be literally dripping muddy water on our tile floor, since he wouldn't remove his wet uniform in the hall bathroom and wring it out. We had to clean our own rooms, which he never helped do, so I'd find myself cleaning after him, and even then our floor was always dirty & gritty.
He also kept fully raising the venetian blinds on the windows of our male-only dorm, even at night when I'd be undressing for bed. When I pointed out that the public mall outside was open to females who could see us clearly with our room lights on, he replied that girls loved to see his "bod". I replied that I didn't want my own naked "bod" viewed by strangers walking by, but he wouldn't cooperate.
Army: As an unmarried buck Sergeant E-5 I only rated a 2-bed room in barracks. The other soldier was actually not too bad a roommate, except he liked to sing a lot, and badly. None of us could be too messy, thanks to regular inspections, but he did keep late hours, waking me up when he'd return from the enlisted club or off post, often banging around drunk.
Then he went on leave for 2 weeks, and one day I came back to find his bunk stripped and his wall locker empty. I went to the Orderly Room to ask the First Sergeant if he'd been reassigned, and I was told he'd been killed in a car crash in his home town a week earlier. His personal items were being shipped to his parents.
I complained that I'd like to have been informed immediately, since I did share a room with the guy. And so that I could have sent my condolences and flowers to the funeral, which had already been held. The First Sergeant agreed I should have been told sooner.
I also felt some kind of guilt, for not having been friendlier to him. And for wishing to have the room to myself again, the way it was for some months before his arrival. It made me wonder, irrationally, if my desire for him to be gone had been a factor in his death.