Okay, sorry for the fancy title, but two areas I think that people don't take into account when talking about realism of a story are the sociological aspects. I'm talking about politics, economics, psychology, and so on. These aspects though I would argue are more important to fleshing out a world than the physics of it, and is also ESSENTIAL for characters who have mental illness, the latter I'm talking about psychology obviously although others fields will affect that. Let me start by saying that I'm not saying that every story needs to have realistic sociological elements. However, if a story is trying to be, "hard," in the sense that it's trying to make the world as plausible as possible, this element is just as mandatory as the physics or the what have you. More importantly, for stories that want to heavily explore the setting, or the character personal beliefs about anything, should have a tight grasp of these subjects. For example, if a character is a Communist, well, what type? There are LOTS of types of Communists. Anarcho-Communists, Council Communists, Stalinists, Leninists, Trotskityes, Maoists, and so on. Also, the writer may end up coming up with something very different from communism. Also, one needs to realize what differentiates Communism from Socialism, and from Fascism. That last one may seem obvious, but actually, if one approaches the analysis a certain way, Stalinism is a "left-wing," form if you will of Fascism. Another example, dealing with psychology, is if a character has schizophrenia. Well, for one thing, there are many subtypes of schizophrenia, and whether it's even one mental illness has been put under debate. One needs to know the mental illness, especially since just because a character is mentally ill, doesn't mean you can have them do whatever the hell you want them to and it not be out of character ever. People with mental illness respond the same way over and over again to the same situation, which will appear irrational to us, but to them, is very rational for some reason. Now, I'm not saying anyone here is responsible for doing really badly with these subjects, and I'm not saying that they should conquer the story. My point is that they should be kept in mind, especially if a character is specifically political and/or has mental illness of any sort. I hope I didn't alienate anyone with any of this.