To build any believable world of the future, you can’t just have cool gadgets and great characters; the cultural milieu within which the characters dwell is important believability. Think of, for example, Blade Runner. The dark, noir feeling makes me (I won’t dare speak for others) like I’m in a living anime. It was believable and you could get a sense of the economic system just from the buildings and the people’s clothes. Now juxtapose that with, say, The Fifth Element. Where things are a little less clear (again, to me at least). It felt like a generic version of “the future.” With this in mind, I think this is a good article to read to consider the world you’re trying to build.