hollywood absolutely will never understand that a book is not a movie and a movie is not a book. they need to be separate entities; this does not mean that the movie must be inferior to the book, rather it means that you may have to invent things that didn't happen in the book in order to achieve some kind of congruity with the stories. narration is the laziest bullshit, and happens in 99% of these shitty adaptations.
for instance, in the book version of misery, whats-her-face actually severs the author's feet with a hot axe. they decided that it would be too much for the movie. visually it's difficult, and emotionally you have a hard time imagining you are the protagonist with no feet up there on the screen. breaking the ankles was very very effective. it just worked better. if that movie were made by someone less confident, surely they would have neutered the fucking scene and made it have zero emotional impact.
another example is that in the book version of deliverance, the end of the journey finds our erstwhile protagonist changed. however, he looks back to the experience as a sort of catharsis, almost a religious experience. catharsis through violence is a great theme, and it works very well in the book. in the film, he wakes up from a nightmare of (if i recall correctly) a flooded church graveyard. the violent catharsis has left him no better; it's a peckinpah type of ending. it works very effectively and i would argue that it is one instance in which the movie is as good as the book.
(ps v for vendetta sucks balls)