I lived in some pretty iffy neighborhoods in my salad days and had terrible neighbors. There were the two young black girls who shared a house with us - both of us on the second floor, their apartment on one side of the house, ours on the other. We had a regular door at entry level that had a lock on it, but Heifer and Heiferella would constantly keep that door open AND their door open. In the winter, with snow on the ground. I think they were turning tricks.
Years later I lived in an old professional building that had been turned into apartments. A lot of us in the building knew each other, it was an artists' colony of sorts but a few losers trickled in over the years....and that time I did have a whore as a neighbor. She had a 2 year old kid and would turn tricks all night - don't even want to think about that. A friend lived in the apartment underneath and was just driven to madness for the time she was there (which thankfully wasn't long). Her tricks would stand in the street and yell up like she was fucking Rapunzel or something - she looked like an extra from Deliverance.
Another neighbor was Bob, an old gay man who was slowly losing his mind AND his hearing. He was always inviting these guys over, rough looking dudes who we eventually realized were hustling, and when he wasn't home they'd go knocking on other people's doors to try to ask them for money or, for the gay men, interest them in buying their wares. Had to call the cops on them only once, they never returned (which tells me they probably had multiple warrants).
Bob also had a nasty habit of starting to cook dinner, then drinking a bottle of Riunite and passing out on the couch, which of course created several small kitchen fires. We called the fire department and cops and he was SO livid that we'd done that - loony ass bitch, as if we were supposed to wait for him to wake up?
I did like that place, though, for my hot neighbor, who would always make lots of loud noise when he was fucking his twinks. That noise, I never minded. My bedroom and his shared a wall and I admit, I was woken up a few times by the noise and ended up rubbing one out because it got me worked up.
Those were my cheapo places (nothing that affordable exists any more) but money doesn't make people behave any better - more recently, my partner and I lived in a decent condo where the guy put loud club sized speakers in the wall and blasted music and TV all the time. It took months of board mediation and several neighbors filing a joint lawsuit to convince him that no, you couldn't do that in a condo building, where everyone shared floors and walls.
We're in a lovely place now with great neighbors but right before we found this place we had a rental. Halfway through our lease term the place changed hands and a halfway house moved in, and so we had a bunch of junkies who sat in the back yard talking all night, because they couldn't score dope or whatever and needed to pass the time. And worse yet, one of them was hard of hearing and hours away from his fiance, so he'd be out there yelling into the phone at 2 am. We'd get to sleep at like 5 am and have to be at work at 8. A nightmare.