This is an edited version of a comment I made in reply to yet another forum dweller that was arguing that the lack of a proper US culture was the reason why so many Americans still consider themselves Italian or Irish more than a century and a half after their families emigrated.
While it is true that European countries have a longer history, in many cases parts of their heritage is borderline fantasy, often heavily manipulated during the 19th century nationalist movements. [As examples, German/Bavarian lederhosen were not historically particularly German, and their modern form originated in the late 19th century; baguettes were invented in the early 20th century, etc.] I’m not saying this type of “heritage” is wrong, just that you don’t need to have been doing something for 800 years before calling it heritage.
In general, many of the historical things Europeans are proud of are from the 19th century: German and Italian unification, the French revolution (okay, very late 18th) and Napoleon, Queen Victoria and the British Colonial Empire (started earlier but greatly expanded at that time). All of this happened after the US signed its constitution.
On the other hand, the US does have plenty of heritage of its own (the revolution, civil war, and hell, the sheer influence of American democracy and ideals on the rest of the West and the world).
As for culture proper, it’s just strange to claim that the US doesn’t have one. You have distinctive foods and cuisines (burgers, barbecue, fried chicken, Tex-Mex, etc.). Americans have a style of urbanism: a small town in Pennsylvania looks like a small town in Oregon, and looks nothing like a small town in Switzerland. They love brick buildings and high-risers. They have an immoderate love of cars and pick-up trucks. They eat dinner way too early. They value hard work and work long hours. Social life, at all stages of life, is markedly different from what it is in Europe. You’re very religious, and fairly materialistic. The American dream. I could go on.
You could say that’s a collection of stereotypes, but that’s what culture is: traditions, ideas, values and stereotypes most people fit in, that makes you feel like you share something with others. They’re all actual things that make foreigners experience a cultural shock in the US.
I’d add that many American cultural inventions (the modern forms of Santa Claus and Halloween, jeans and t-shirts) have been exported so much that they don’t feel American anymore. I’d argue that shows the worldwide influence of American culture. Heck, some people in European countries don’t even know how their own legal system works because all they’ve ever seen is American criminal movies.
[Note that I’m not taking position on whether American culture is good by any particular standards, or whether its prevalence is a good thing for the rest of the world, just saying it very definitely exists. Also, I realize this answer is very West-centric, and plenty of non-Western countries have complex cultures, I’m just answering with what I know :).]