The USA is a huge nation, divided into smaller states. Is there such a thing as Amercian culture - things that look the same from the north to the south and from the east to the west. MOst Americans woul probably be a bit sceptical, but sure there are! To someone visiting the States from for example Europe or China, the USA seems like a fairly conformed nation. Sure, the accent differs a bit between the north and southern states, and sure, perhaps the northeners are a bit more open-monded in general. But the people a loud, friendly and quite welcoming as a people. As Americans.
I notice this when calling customer service for different airlines. I travel a lot and find that most airlines have really friendly customer service. If you compare with ountries like France or Italy, the American airline customer services are top notch. They are clear and polite and go out of their way to halp you out. I have experience from several different airlines, like Alaska Airlines customer service and Virgin America customer service, and more that I can't remember to point out.
Another thing that strikes you when visiting the USA from other countries is the size of everything. And the quantity. Visiting a Super market is an experience the first times, becuse the rows for cereal is approximately the same size of an entire Super market in most other countries. WHat's the need for all that many choices, really? It's an American thing, I suppose.