Because of Winn-Dixie
There are a lot of minor differences between the book and the movie (most notably, AnnaSophia Robb is in no way the red-head that the book describes and Dave Matthews doesn't really pull off the slow, socially awkward Otis). For the most part the differences, while annoying, don't really damage the integrity of the story. It is, in fact, far more dramatic for Winn-Dixie to show up at the very end of the party rather than waiting at the house when Opal and the Preacher return. Most notably, and most confusing for me, was the addition of two new characters: the sheriff and the head of the trailer park. While these characters added humor and drama as well as introducing small amounts of exposition that had previously been expressed through narration, I'm not sure those elements were necessary, nor did they feel as fully fleshed as the other characters. And given that a major focus of the book was the sorrows that we all experience, I didn't feel like those sorrows really came through in the movie. In this case, you're far better off reading the book than bothering with the movie.