Authenticity of dialogue is magic for a reader. I think every writer is limited by where he's from, particularly someone who has spent his entire life in one region. This is, of course, a mixed blessing. A writer who has lived only in Nebraska, for example, has to write about Nebraska. This is not a problem to be lamented but it is a determiner of who your characters will be.
Writers just tend to write about their environment.
If the South tends to be more poverty stricken, or has a less-educated population, or the politicians seem more arrogant, or there's a more intense devotion to religion, that's just the way it is. This quality doesn't seem to surface as much with non-Southern writers. Much of my early reading was devoted to folklore and the likes of Mark Twain. Tall tales, with their hyperbole and outlandish plots, seem to have had an effect on my writing. I hearken back to the days when television was a minimal presence in American life.