Deal breakers? In terms of what I won't read?
I'm not big on thrillers. I don't like scary movies, and I won't read scary books. You can thank the movie IT for that one.
I don't like books that deal with infertility. In fact, if I know ahead of time that struggles with infertility are in the book, chances are I won't read them. They hit way too close to home for me.
I don't mind romance books, but I don't like the over the top, annoying, nothing but sex scenes in them books either.