> Americans are extremely polite
Having grown up in the UK and living in Australia, I do not find Americans polite. To me, politeness is "please", "thank you", "may I have", etc, whereas "I would like a latte today" reads to me as a demand. In context it's fine (it stands out a bit but not in a problematic way), it's not particularly rude, but in general just stating your desires is not considered polite in my experience in UK/AU.
There are some other parts of American English that may be considered polite, I notice a lot of US folks addressing me as "sir" for example, but this sort of thing comes off as insincere or even sarcastic/rude.
I know this is how people communicate so they don't really bother me, I'm used to them and accept that different people have different expectations. I also understand that Americans might believe they are being polite and consider me to be rude, but I think this is why blanket statements like "Americans are extremely polite" are just missing so much cultural nuance.