Well it's one of those "when cultures collide" things. One of the better part of my education at Duke was, when dealing with Yankees, dispense with politeness and give them crap right back. They won't take offense.
My room mate, from Richmond VA, went to see Duke play in the Palestra in Philly. He went to concessions to order a soft drink. He ordered a "Coke" which is not the local lingo. So they had to have an interchange over that. When he got his drink, being a well brought up Southerner, he said a sincere "Thanks" which earned him a dirty look from the concessionaire who figured he was being a smart a$$.
I was raised in Richmond and my step-father (originally from NJ) was a stickler for Southern manners.
That made us an oddity when we went to see our weird Yankee cousins. (Wierd because they were just strange, being Yankees had nothing to do with it)
Stop saying M'am because my Aunt thought is sounded smart-assed? I don't think so. Who cares what she thought, my father would send us to bed if we left M'am and other Southern words of respect out of a conversation.
In my adulthood, we lived in CNY for 17 years. People are people, but there are regional differences. My friends used to laugh at me. They said I sounded like Sgt Carter when I would say to my kids "Yes, what?" (Answer: "Yes, M'am')
To this day, I Please, Thank you, Sir and M'am 95% of the time. I am 52. I also make use of those NY gestures of disrespect, LOL! I am diverse.