[cocktailpeanuts]

Unless you've lived for meaningful amount of time in various cultures throughout your life, this type of stereotype ("Americans are such and such") tells more about yourself than what really is true.

I say this because I have lived in multiple countries/cultures and have seen many people who say the same thing. Regardless of which country you live in, there are people who talk about how some bad human trait is specific to only their culture. If people from all other countries say the same thing, it probably means it's not unique to only your people.

Also, this is not an American thing. This is called "courtesy".