"No matter how good something is, if you were expecting something else, you'll hate it."
People ask me periodically why I chose to be Mira Grant for my science fiction when I was already happily myself for my urban fantasy. My standard answer is all about marketing and branding and setting expectations, and all of this is completely true...but the real answer is all about Vegemite. People who like me for me were going to know that I was Mira Grant, because it was an open secret, and they were the ones who'd just be expecting my words. People who like my urban fantasy weren't going to pick up a book by someone else expecting magic and hijinks. And once Mira established a readership of her own, people who liked science and zombies weren't going to up my books expecting the dead to walk.
The Vegemite effect explains a great deal about how we approach media of all types, not just books, but comics, movies, and television. There's a lot to think about. And if you've ever wondered why sometimes I say "this is salty" repeatedly before I hand you something...
...well, there you go.