This is one of my favorite quotes from Gail Carson Levine's Writing Magic that I was reading today:
So what makes the difference between caring and not caring? The author's
cruelty. And the reader's sympathy. We Keep turning the pages because we're
worried. Horrible things are happening to the heroine (some of which she may be
causing), and we have to find out if she comes through them all right.
I love this because it's so true. I did not really identify with Bella (from the Twilight and New Moon series) until New Moon when something horrible (which I will not reveal in case anyone is thinking about reading or reading either of these books) happens to her.