It’s weird, I’ve travelled for work and pleasure more than pretty much anyone I meet (I’ve visited 90 countries, worked in 21, lived longer term in 5. Currently settled West Coast US) and I’m somewhat of a fast food connoisseur lol - KFC, Domino’s, BK, Pizza Hut, etc are all without exception better in Europe and Asia with the exception of ,in my opinion , McDonalds. Maccies is better here as a rule. Sure you get the shitty franchisees sometimes but generally speaking!
This is a semi controversial opinion so, it’s interesting you feel the same way!
It's not a big difference but Japanese burgers are smaller (of course) but the buns aren't small enough. So there's just way too much bread in my experience.
Also, US has a mango pineapple smoothie that's really good. I refuse to look up how much sugar is in it.
(Btw, I like US McDonalds better than Japan's, but maybe I'm the only one that thinks this.)