You hear the door open. Nobody knocked. Somehow your neighbor is already in the kitchen. Sitcoms gave us the people next door we loved, tolerated, hid from, and occasionally wished would move three states away. Kramer raids your fridge. Urkel destroys your furniture. Flanders is aggressively pleasant. Wilson has suspiciously perfect advice waiting over the fence. The best sitcom neighbors aren't background characters—they're walking plot devices who can wreck an evening just by showing up. But what actually makes the ultimate neighbor: laughs, chaos, loyalty, or being someone you'd genuinely trust with a spare key? Pick your side. The door's already open.