Conversely, I think successful games are ones that are developed efficiently, appeal to a wide audience, have good marketing, solid QA, and features that are appreciated by gamers and lauded by critics. I suppose that's just common sense, but some people can lose sight of what's important when they're focused on something else. I think there's a lot of hard work that gamers don't believe happens. If a game comes out buggy or with a few less features than it originally was supposed to have, people can go berserk. A lot of times, I think gamers wind up believing that the developers are a bunch of lazy, beer-swilling buffoons.
Development is a lot of fun, but it's incredibly difficult as well.
Something that initially seems very cool and very doable can wind up being a nightmare to implement, for both technical and gameplay reasons. When you have a good understanding of the basis of our perception of history and culture, it's easier to branch off from it in interesting ways. I like to compare it to art. If you want to be a fantasy artist and illustrate wacky mutant creatures, you need to understand how bodies go together, how muscle attaches to bone, how bones attach to each other, and how internal organs are placed. Once an artist understands those fundamental facts, he or she is able to deviate from them.