Neighbors in apartment buildings live 10 feet apart for years and never learn each other's names

You have lived in your apartment building for 2 years. There are 20 units. You know your next-door neighbor's name (you introduced yourselves during move-in) and recognize 3 others by face. You have never had a conversation longer than 'hey' in the hallway or elevator. You do not know that the person two doors down works in your industry, the person upstairs is from your hometown, or the person on the first floor has a dog your dog would love to play with. So what? Your apartment building is a pre-built community of 20-40 people who share physical space, common amenities (laundry, lobby, roof), and local context (same neighborhood, same landlord, same street noise). This is the exact setup that creates friendships: proximity + repeated unplanned interaction. But apartment buildings have no social infrastructure. There is no directory, no shared message board (or the one that exists has a 2019 notice about recycling), no events, no way to discover shared interests. The building is an antisocial architecture: you enter through a locked door, walk to your unit with eyes down, and close your door. Twenty potential friends live 10 feet away and you will never meet them. Why does this persist? Building managers want quiet tenants who pay rent, not a social community that might organize tenant complaints. No building provides resident directories (privacy concerns). Nextdoor covers neighborhoods but not individual buildings. Building-specific apps (like Latch building apps) exist for package management and maintenance requests, not for resident connection. The physical design of apartment buildings (long corridors, heavy doors, no communal gathering spaces) actively prevents the spontaneous encounters that create connections.