What I am relaying to you is based on personal experience growing up in the lower middle class / poor American south. It's still that way when I go back to visit. As far as "the media version" of the American south goes, I have no idea what you're even talking about. Perhaps you're in a high socioeconomic status bubble and you need to drive 45 minutes in any given direction and re-test your conclusions.

At any rate, I live in the bay area now and I very rarely encounter issues with un-friendliness in the contexts mentioned in this thread. The lack of effusive friendliness that I do encounter for the most part is cultural. Which makes sense, as the bay area is extremely diverse culturally.