If you are loud, condescending and generally obnoxious, that might be a clue
As much as I hate to admit that...it’s true. I came from “up there” almost 40 years ago and landed in PB County, as did many, and by your description you could tell who was not “local”. Now living in a part of Florida that is more like the “south”, have kids and grandkids who are proudly native Floridians.
I can tell when someone is from metro NYC from the accent and the attitude—and I live in CT!