"We read to know that we are not alone." - C.S. Lewis
Book turned movie and completely desecrated.
Oh....this is a hard one. I have a few categories that I put book to movies.
1. Books that have miraculously been perfectly transferred to the movie. There are little to not changes in the plot, pace, characters, etc. If there are changes they are small additions that add to the story. This is rare to find, but in my opinion "The Lion, the Witch, and the Wardrobe" (the newer one) achieved that to perfect.
2. Books that the movie ended up being much better. In this case the book was good but the movie better. In my opinion "The Princess Bride" is one of those cases. Another rare category.
3. Books that have been transferred to a movie well. The essence of the plot was captured, the 'feel' of the book present in the movie. In other words, the movie supplemented the book well. This is a slightly more common occurrence. In my opinion such movies include "The Lord of the Rings", "Hunger Games", and "Jane Eyre."
4. Books that have been transferred to a movie that is good but don't compare it to the book! This is probably one of the most common kinds of book to movie adaptions. The movie is good in and of itself but follows the plot of the book very loosely. Such adaptions include: "Percy Jackson" and "Prince Caspian"
5. Books that have been turned into movies that are terrible movies and terrible adaptions. "Eragon" and "Inkheart" are prime examples of this category.
6. Books turned into movies that...well make you wonder. This is the worst category in my opinion. It's ultimate example being "Ella Enchanted." Yes, the movie was good if you hadn't read the book (which is much better). But honestly...from an adaption point of view...we even call it an adaption? If a few names had been changed and the title changed it could hardly be connected. The two works were nothing alike except in a few critical aspects (basically the premise...).
All of that said, because of my love for Ella Enchanted that would be the most completely desecrated adaption in my opinion, though the movie alone was not bad.