First of all, let’s try to avoid American-bashing, and stay respectful to everyone.
I’ll start: for me it’s the tipping culture. Especially nowadays, with the recent post on [email protected] with the 40% tip, it just seems so weird to me to have to pay extra just so that menu prices can stay low.
Politeness. Americans are super polite and I really like it. If you spend extended time there the whole “Have a nice day” thing becomes really nice.
I find this to be highly regional. Plenty of places will ignore that you exist beyond the payment. A minority of places perhaps, but the hospitality isn’t universal.