When I had roommates, I think I was that nightmare roommate. Namely, I literally never cleaned my side of the room and kept extremely odd hours (4am bedtime). Pretty soon, my half of the room looked like it was straight out of hoarders, while my roommate's side was clean. I'm sure he didn't enjoy it.
I eventually got extremely tired of trying my best to even be slightly reasonable, so I decided to not have a roommate the following year. Best decision ever
However, I do still have a couple less than stellar experiences:
1.) That year, my roommate kept extremely odd hours in the opposite direction. He went to bed at 9pm every day. I never figured out when he woke up; according to him, 6am. You can imagine the 7hr of tension between my bedtime and his bedtime.
2.) I once had a serious stoner housemate who smoked pot day and night. He also never cleaned up, but additionally, he'd forget to turn off ovens and stoves, leave all lights on overnight, have the heater on 80 while windows are fully open, and generate noise complaints all hours day and night.