I'm still young enough that I get "Miss" when people talk to me. I am ok with "hun" but anything more affectionate than that, from strangers anyway, makes me feel weird. I am definitely not ok with "young lady" or "girl" :P

I am from Canada, and growing up, in school and whatever, the generally accepted titles were "Sir" and "Miss", regardless of age. I very rarely heard "Ma'am" used, and always felt uncomfortable using it myself.