Movies based on books

What are your opinions about movies based on books?

I usually don't mind. What I can't stand is when someone makes a movie based off a book, and it turns out to be extremely horrible; I cannot stand that.

But most movies are based off of books anyways.

Some movies based on books can be brilliant, but I often I find that if I've read the book already the film often disappoints. It's pretty difficult to fit a novels worth of story into about 2 hours.

Well, it depends on how faithfully the film tries to follow the book, and having a good cast and director.