How well do you know your neighbors? Maybe not as well as you might think. The Nextdoor app is a good way to get a feel for a neighborhood, at least based on the various complaints that people post there. While the app is supposed to be a way to connect to your fellow residents to sell items, advertise events, get to know the area, or address community issues, not everyone uses the app as it was intended. In fact, sometimes it seems like most people misuse this app — and that results in some si…