Uh, fun. I live in the real world, you don't get much more realistic than that, so why the hell would I want realism in my fantasies? I don't even want realism in real life, that's why I view it in fictional terms. Also, Mario, Zelda, Metroid, many FPS's (they may try to be realistic by making everything brown, but health kits and portable arsenals aren't realistic), RPG's, and countless other games aren't realistic, but they are fun and have good art, and that's what matters.
I do like some scientific accuracy, however. Just a buff about that.