Nobody wants to have bad blood with their nextdoor neighbors—since you literally can't get away from them. And yet, there's something about sharing walls or proximity with strangers that seems to lend itsself to conflict.
1.) From shittymondaymorning:
This is more of a funny story than a neighbor from hell. But in our apartment, we kept hearing massive bass (think like a rhythm game) starting at like 6 pm to sometimes going till 11 pm, and it sounded like it was localized right above our bedroom. Finally, one night I go up and bang on the door, but they don't answer. About an hour later, I hear moving around in the apartment above me, so I walk out, hoping to catch them either on the stairs or so I can knock on the door again.