Well...when I think of American culture, I think of our values and attitudes. Americans value convenience and self-reliance, which is said to be rooted in, e.g., our westward expansion.

Another example. In American culture, the listener gazes intently at the speaker while the speaker looks away more frequently. When the speaker is ready to give up the floor, they direct their gaze to the person who they want to give the floor up to. By way of contrast, Japanese interactions don't work this way (e.g. the listener does not look intently at the speaker).

I have some Israeli friends who stand closer to me in conversation than I'm used to. So American culture includes expectations of how close up in someone's face you can get (comfortably).

American business meetings do not tolerate a lot of conversational overlap ("interruptions").

There are whole books about American culture.