What changes have you had to make in your assumptions about how the process of food consumption (buying, ordering at restaurants, etc.) works when you moved to a different region of the country? What things that are simple facts of food life to the natives strike as odd or annoying? What everyday things did you take for granted that don't seem to exist in your adopted home (discounting the obvious regional produce and specialties)? What differences in terminology have provoked confusion or amusement?
(I'm really thinking about US regional differences, as changing countries means a world of difference even for seemingly similar cultures.)
I moved from northern California to New York City some years ago, and find myself still very aware of a few small differences. Why, in the age of 24-hour everything and a thriving wine/food culture, has New York not lifted the blue laws that prevent supermarkets from selling wine and everyone except Vintage NY from selling it on Sunday? Why is it that here everyone seems to offer (and use) straws to drink soda or water from cans or bottles? Why must I pay extra at a deli or diner to have lettuce and tomato on my sandwich or burger, and why does a "plain" burger not include these, but invariably includes coleslaw and a pickle spear? How about that "California salad" on all the diner menus (cottage cheese, jello, and canned peaches have what to do with California? At least "California" sandwiches with sprouts and avocado buy into a stereotype). And then there's the rules for ordering coffee--much less prvalent now with all the coffee bars and gourmet shops, but if you're stuck with the corner deli and forget to specify exactly how you want it, you get "regular," i.e., with cream and sugar.