I'm guessing you haven't driven I-4 in Florida. Rated multiple times as the most dangerous stretch of highway in the US. People just change lanes without indicating or even looking. It's crazy.

https://www.bcmillerlaw.com/posts/interstate-4-in-florida-tops-list-of-deadliest-u-s-highways/

The most frustrating drivers I've ever encountered, however, were in the Northern Virginia/DC area. So much entitlement. People stopping their cars in all sorts of places where you're not supposed to, putting their hazards on as though that makes parking anywhere legal. Driving aggressively. Just generally entitled, crappy drivers (maybe because the population is so heavily made up of immigrants from countries with different rules--just a guess).

I've been through most of the US at this point and lived in a handful of states. Those two are the worst. LA sucks, too, but that's mostly because of traffic.