Hey, I like what you've done with the place.
I've eaten plenty of fast food in various places around the world, but never exclusively fast food. However, I have a couple dumb/regrettable food travel anecdotes.
I was just in Russia and repeatedly tried to get fast food, but they don't seem to get the concept. It was always slow and disorganized, and never clear how to queue up. I'd usually give up and go to the grocery store or a Russian restaurant, where I'd get faster service from a waiter. Ironically, the local Russian fast food chains had it figured out, but not McDonald's or KFC.
I'd also successfully gone years of my kids having no idea what McDonald's was until we were in Prague last summer. I was working so we hired a local part-time sitter to get my wife some relief, and she's the one that brought them to their first McDonald's. Of course we live in the birthplace of McDonald's, so now that we're home, they ask for it all the time and claim nostalgia for the Czech Republic.
Finally, when I was in Austria in the 1990s, I somehow accidentally ordered a totally disgusting dish three times, under various names: basically unrendered, grisly pork fat mixed with raw garlic and spread on bread. I think this was usually because I was ordering the cheapest item on the menu. And because I was broke and timid, I never sent it back and got something else, but forced as much or it down as I could until I was no longer hungry.