I'd say that of Southerners. I think outsiders, particularly from the East Coast, perceive them as polite and accommodating because they don't act like entitled assholes outright or sound like they've been chewing on rusted metal all day. Nope, they're just passive aggressive, and just as suspicious and territorial as anyone else.
I'm reluctant to speak ill of the Hill - I have mostly sparkling memories. But once, when I lived in Athens, I drove up there with a group of friends to see a Merge Records showcase at Cat's Cradle. I guess we looked like dumb college boys. Anyroad, one of my friends bought a CD at one of the famous record stores there (I can't recall which, and I don't know if any of the ones I remember are still there; Schoolkids, anyone?), and the clerk said, "I bet you're here for MergeFest." Uh, yeah. "How did I guess?" Straight-up dick. They're in overabundance everywhere.