Being born and raised in Decatur, Alabama I was taught certain principles by my parents and family. For instance, I say "yes Ma'm and no sir" to people at least 2 decades older than I am, I say hi or "hey" to others as they pass (not everyone, but usually those I make eye contact with), and I am friendly and treat people with respect, from the homeless man on the street to the cafeteria lady serving food or the CEO of a company. This is how I was raised, and this is what I try to practice on a daily basis.
Based on my experience having lived in living in DC, L.A., Sendai and Tokyo Japan, I do feel that such principles are practiced more by people from the South. Taking this step further, I would also say that blacks and hispanics, especially practice the principle of "speaking" to others like them, especially in situations where it may be unusual to see each other like ummmm.... Tokyo Japan.