A vague idea that has always been with me is a character who is a food snob or extremely healthy traveling with friends/colleagues and ending up in a situation where fast food is the only option for the reasonable future. At first they decline to eat, but their friends pressure them into it (we're not stopping anywhere else; you can't go to bed without dinner; we don't have time to get real food right now; stop being such a brat; etc etc). They try to get the healthiest thing they can, but it still upsets their stomach. At first, their friends think they're being dramatic (we get it, you don't like fast food; sorry princess, we'll try to accommodate your royal standards you next time; you don't have to rub it in) until they actually start vomiting
(Bonus points if it's food poisoning, not just a bad reaction to hyperprocessed food đĽ°)
















