When you read John Scalzi’s blog, you learn that science fiction writers have problems above and beyond those of ordinary writers:
World building is hard. You want us to have to build an entire universe from scratch every single time we write a book? Well, okay. You want us to have to run a marathon every time we walk down to the corner store to get some milk, too? Or maybe assemble a car from the wheels up, every time we want to drive to the mall? We spend all this time building this ginchy universe and its rules, and then you say “Oh, that world again?” No one ever pulls that shit with other genres. People don’t go up to Carl Hiaasen and say “What? Another book on Earth?” And he didn’t even make up that planet! It’s an open source planet! Damn slacker.