How do you feel when an adapted film's story deviates from the original material?
Depends on how they do it. The first two Harry Potter movies were excellent, but I wasn't happy with the later movies. Also, they did an awesome job of extending Matilda into a movie and keeping within the spirit of the book. But I have yet to see an adaptation of White Fang that doesn't make me want to hunt down the director and beat them to death with a sack full of copies of the book. Hardback copies, of course.