I've lived in plenty of places, and having been a journalist, I keep an ear attuned to regional "slang" (for lack of a better term) unique to each place I've lived.
1. In Alabama, a "buggy" is a "grocery cart" anywhere else in the country. "Y'all" (abbrev. for "you all") really is in common usage. Instead of asking for food "to go" you ask for it in a "to-go box."
2. In Montreal, you don't ask for a hamburger or hot dog with "everything on it," you ask for it "all dressed." It's not a "convenience store," but a "depanneur" (sp?). It's not "shopping off the grocery list," but "doing an order."
3. In Southern England, it's "All right?" instead of "How are you?" Lots of other differences, of course, but the ones that jump out at me now are asking for "20 cigarettes" at the store rather than "a pack" and "building society" rather than "credit union."
What kind of regional differences are there in English where you're from?