There are SO MANY. Like this is one of my great spaces of pedantry.
But one thing that always pisses me off is the Chicago in My Big Fat Greek Wedding, where everyone but Toula is somehow blonde. You wouldn't even find that many blondes in andersonville in the early 2000s!
Prompts a fun question: whats the most niche historical inaccuracy in a piece of work that annoys you
Not like 'oh they were referring to the wrong king' , more 'they had the wrong king on a banknote in one scene'