Subverting Expectations
One of my favorite books ever, Anna Dressed in Blood, is a YA horror novel by Kendare Blake. I think the main reason I found this interesting, and just loved it so much in general, is that it's very unique from other books in the same category. As far as I know, there aren't too many horror books in the YA spectrum; in fact, I can only think of a few off the top of my head. To be clear, I don't think it's a terrifying story. I don't think it's going to give most readers nightmares or anything like that. But, it does maintain a sense of creepiness all the way throughout, and there are a lot of horror aspects. People actually get dismembered in this book, and being YA, these scenes aren't described in great detail, but still.
The novel also features a very unconventional romance, one between a human and a ghost. I thought it was interesting to see how this relationship played out. Another positive point is that while there is a main romance, it's not the focal point of the story. The characters aren't constantly gushing over each other and blushing. You can still clearly tell they care about one another, but it's executed in a more subtle way.
To me, what makes Anna Dressed in Blood so good, is that it avoids the usual YA pitfalls, and even subverts them. There are characters who seem like true and tried tropes, only to quickly show they're the exact opposite. And there's the whole dismemberment aspect again. This book isn't at all what you'd expect a YA novel to be, and for that, it's truly a great read. I believe it's one both young and older readers can enjoy.