I love the movie Warm Bodies because it's a teen rom-com set in a post-apocalyptic world that is also a great metaphor for the epidemic of depression in the U.S. And because the saying goes ‘the book is always better', I picked up the book from a dusty bookshelf and started reading.
Books like these make me sad: the author had a solid idea and a great message to tell the world, but the execution is something to sigh and groan about. The romance was pretty insta and only happened because of her dead boyfriend's memories and feelings circulating in R's brain. In fact, I have no idea if R really loves Julie (who is the true manic pixie dream girl) or if it's just Perry, the dead boyfriend, placing these thoughts and feelings.
I think the message of this book is great: when the world's crashing and burning, you can still be able to enjoy life. But between R being a zombie and witnessing all of Perry's memories and thoughts, it really should feel that Perry should be the protagonist. He's far more fleshed out than R, is more interesting because of it, and actually has good groundwork for a character arc.
Perry obviously had severe depression in life, adopting nihilism and staying in a pessimistic mindset. If he got what he wanted, death, but came back as a zombie and saw what he wanted was worse off than where he was, it would make a compelling story and more articulate the message of the book: when the lights go out, that doesn't mean you should too.
The movie, I feel, really excelled here in just sticking to a teen audience by only conveying one message of the book: have compassion for people who have mental illness. Not to mention, at the time more teens could relate to the allegory of depression. This theme doesn't really come up in the book all that much. The first few chapters set this up, only to be interrupted by Perry's story for most of the book, and then be revived in the last few chapters.
TLDR; good message but horrible execution. The movie was better.