I sometimes wish that people who didn't enjoy a book were more vocal about it.
Often I'll read a book and nearly everyone will be saying how amazing it is, whilst I can't see what they're getting at and think it's boring, badly written etc. (e.g. This Is How You Lose the Time War, All Systems Red). Particularly on GoodReads, most people seem to be positive about books.
I guess it's easier to write a review about a book you liked than one you hated?