I think a lot of their culture revolves around adolescence. Sports, music, movies, fashion etc. are based on juvenile traits, where talking, actions and getting attention are more important than more mature things like listening and compromising.

They’re not all like that, but there certainly are many who get through life in an American cultural bubble. When you reach your early twenties you probably think you’ve got everything figured out. That will last until you encounter other cultures that can challenge your views. A lot of Americans don’t encounter other cultures.

I know plenty of Europeans who are similar, but they don’t appear as one group. A German ignorant appears and speaks different than a Swedish ignorant, and both countries are known for having a similar superiority complex based on their own domestic successes. The Americans are in a disadvantage here, since everyone can hear and understand them, and there’s quite a lot of them, so their presence is just a lot more obvious.