I've been lucky. Never had truly insane neighbors, but in my last apartment I had two half-crazy ones:
- We had a house party on a Saturday night, nothing outrageous, just some folks and not too loud music. At around 11 pm, neighbor #1 banged on the door. When we opened, he yelled, "Keep quiet! Normal people work in the morning!!". "On a Sunday, what are you, a priest?", we didn't answer.
- One of my bedroom walls was adjacent to the next apartment, and neighbor #2 used to constantly remind me how thin the wall was and how he could hear my every move (I never heard him or his girlfriend, which I figured said a lot about their love life - BOOM). One time he told me, "You know, we can hear you breathe in there!". I told him I would try and keep my breathing down.