Growing up in England but consuming so much US media, these things stand out to me as utterly bizarre when I first learned about it or saw it myself:

1. The pledge of allegiance (reminds me of North Korea documentaries)
2. Flags everywhere on houses (don’t you know what country you’re in??)
3. Singing the national anthem before domestic sports matches
4. Picture of George W. Bush on the wall of the immigration office on the border with Canada, when I first visited with family (everyone in the world knows what your president looks like. This just reminded me of the dictator of Turkmenistan plastered all over their airport on a stopover, and videos of Iraq)