Me too. I might've grown up on the streets of Dorchester and JP,but I married a southern girl and have lived in the South for 26th years. It's just reflex now and that includes calling much younger dudes "sir" as well. A little politeness never hurt anybody.
But I always had good manners,even going back to when I was a rowdy teenager in Boston. I NEVER took a seat on the T,which I rode a lot to work unless it was late night and almost empty. I would stare down young dudes-(some college students) who sat on the T while women and children struggled to keep their balance. It was an evil glare and it almost always worked- I never said a word, but they'd usually get up and offer the seats. My intent was unmistakeable. Then I usually nodded at them when they finally got off their asses. I wasn't really big, but I used to box and did some acting,lol,so I could make someone uncomfortable.
Anyway, I don't buy that Southerners have any better manners than us Yankees,as they call us. After all, don't think you can have worse manners than enslaving and terrorizing people,then instituting Jim Crow. A lot is how you're raised and I was raised right.
But the simple"ma'am" and "sir" down here is a nice thing. Could surely use more of it up there.