I was raised very European so that is a natural part of my vocabulary when addressing other adults. Even when I was a personal trainer I would address my clients as "Mr blah, blah, blah and Ms. blah, blah, blah". Even when they corrected me and told me to call them by their first names I would blush and say, "I appreciate that, however, I prefer to maintain a certain level of professionalism in the client/trainer relationship." And then would laugh at the irony of it because I am such a goof.... but it always worked well.
I even bow my head when I greet people that are total strangers, regardless of their age.
In this regard I am very old school and I like that about me.
As for if someone calling me "ma'am".... when I was younger it sounded funny to my ears but I don't mind it anymore. I mean, WTF... I AM old!