I'm assuming your scoffing because you think America has no culture. The US might be lacking in cultural history, it's only been around for a little over 230 years, but it's certainly not lacking in culture. It's difficult to find a single place in the world that has escaped American cultural influence, which is all the more impressive given its short history.
Art, music, fashion, food all define culture right? I'm sure you experience American versions of all these in whatever culturally advanced country you're from. American Westerns were a culture that defined an era and captivated people all over the world. Modern Hollywood movies and movie stars are seen just about everywhere. Countless styles of music are distinctly American: Blues, Jazz, Gospel, Country, R&B, Soul, Hip-Hop, and Rock & Roll.
There's a pretty good chance that right now you're wearing blue jeans and a t-shirt with sneakers and a baseball hat. All examples of American fashion that's now ubiquitous even in the most remote areas of the world.
People complain all the time about American food. But the fact is, there are successful hamburger, sub sandwich and fried chicken places all over the world, so people must enjoy it. We've changed the culture and way people eat for better or worse, but we also are home to delicious unique things like: BARBEQUE, Cajun/Creole food, Tex/Cali-mex (try finding fajitas and burritos in Mexico), hamburgers/hotdogs, chili, clam chowder, apple pie etc etc.
There's plenty of American culture to go around. Feel free to adopt some more, I'm sure you've already got a good start.