I live in what would be the equivalent of Mayberry, were Mayberry a mid-sized city. There is no six degrees of separation, and everyone knows one another. And if you don’t know them directly, you can be sure that you’re no more than two degrees of separation.
As such, we have a super low crime rate. Except for theft. Theft is, like, off the charts. At first blush, that looks really out of whack, but once you begin to dig deeper, you understand why. This Mayberry-esque feel leads people to let their guard down.