Answer:
Hm. That's a good question. I've never thought about that.
Well, I think most people believe that Americans are all fat, loud, annoying people who like hamburgers and milk shakes.... Not true. And definitely not our cultural identity. Those are all stereotypes.
American cultural identity... it's more like knowing that we're a country built from immigration, and so we recognize that we're NOT really Americans, because all of our ancestors were from somewhere else. So we've got a blend of cultures, and we identify ourselves by our diversity.
Oh my goodness, I am not qualified to answer this question. I have no idea how to answer.
I suppose we also identify ourselves by language, like most places. The majority of America speaks English, obviously. We value knowledge and progress (or at least, most of us do), as well as friends, family, and security. Other than that, I haven't the faintest idea what to tell you.