The settings that really pull me into a neighbors story are the ones that force constant, low-key proximity before anything physical happens. Shared walls in apartment buildings are classic for a reason—you get overheard arguments, muffled music late at night, running water through pipes. That thin barrier creates this illusion of privacy that isn't really there. I recently read one where the main character kept hearing her neighbor practice violin badly through the wall, and she finally knocked to complain, and the whole tension came from that daily, irritating soundtrack suddenly becoming a point of connection.
It’s less about luxurious spaces and more about mundane, slightly awkward common areas. Think laundry rooms with broken dryers at midnight, or having to coordinate trash schedules in a narrow alley. The intimacy builds from dealing with the boring logistics of living close, not from grand gestures. A shared backyard fence where you can’t avoid small talk while gardening, or a mailbox bank where you keep bumping into each other. The setting needs to make their eventual crossing of the boundary feel inevitable, like the geography of the building itself was conspiring to push them together.