In my very humble opinion, the worst fate that a book can encounter is apathy. Ambivalence.
The "Meh" Factor.
You know what I'm talking about - the point where, either halfway through the book, you're wondering what in heaven's name you were thinking by starting it in the first place, or you're part of the way through a 4-, 5-, or 6-book series, and you just don't really want to see it through. I frickin' hate the Meh Factor. Especially in the latter scenario. You feel like you spend so much time getting to know these characters and feel invested in what happens to them. And, then, you get to the point where you just don't give a crap anymore. It's sad.
I've started the fifth and final book in the Fever series, and I'm dangerously close to encountering some serious Meh. I've grown to care about Mac and Barrons, so it's especially distressing when I'm all of a sudden seriously considering cutting my losses and not finishing their story. There's an incredible amount of info dumping in this final book, which causes it to plod along. Adding to that, the author can't just, for the love of God, have Mac make up her mind one way or the other about Barrons. She's constantly plucking that daisy - I love him. I love him not. I love him. I love him not. O. M. G. It's BOOK FIVE. It's OLD.
You may notice that I've been working at this book for longer than the typical two or three days that books of this length take me. The Meh has affected my motivation. Despite all my moaning and complaining, there's no doubt that I will continue and finish the book. Perhaps I'm a glutton for punishment. I guess we'll see.