I've lived in Europe, but I am Icelandic and living in Iceland at the moment.
I've only visited the USA once. I went to New York recently, and it changed my perception of Americans quite a bit. I know it's just a tiny bit of the USA, but it is very diverse. Of course there were all these typical (and sometimes rather amusing) "American" things you'd expect to see, like a huge billboard advertising a movie with the slogan: "action-packed action"...But I don't think that would appeal to *every* American really. There were many things that were obviously very popular, but again, those don't apply to everyone. What I did notice though, and what I think of as very unique for the USA, was the crazy packaging. I don't mean loud pictures with colors, but the fact that every single thing you buy will be wrapped in plastic, put in a paper bag and then handed to you in a plastic bag. You'll have trouble finding coffee that isn't served in a cup made of styrofoam or paper, with a plastic top and then wrapped in a layer of cardboard to make sure your fingers don't get too warm from holding it. Even if you buy a tiny piece of chocolate to go with that coffee you will be asked: "would you like a bag for that"