Before this gets misread I am not saying I don't like film interpretations of books. On the contrary I generally really enjoy them if they translate well and not too much of the source material is changed, examples including Lord of the Rings, Harry Potter, The Ghost, Boy A, War Horse, Life of Pi etc are adaptations of books I have really enjoyed.
However there are a few that made so many changes and poor direction choices that I felt so angry that they ruined a fantastic series of books which I enjoyed so much while growing up and I fear that if I ever read them again, I'll keep on being reminded of these atrocities and won't be able to enjoy them.
The first of these is "The Golden Compass". Where do I start with this one? It doesn't even have the same name as the original book! His Dark Materials was a fantastic young adult book triology and I was really looking forward to the film versions of these books. This film suffered from poor casting choices, toning down from many of the sinister themes, removal of key sub-plots and, worst of all, changing the ending so it was "happy". Apparently they were going to have the original ending at the start of the second book to give the second film "the most exciting beginning possible" but that meant that the film had to do well to warrant a sequel in the first place! Lo and behold a sequel looks like it won't be made after poor box office performance, and it's probably for the best as I wouldn't want the rest of the books being butchered in the same way.
The second is "Stormbreaker". The Alex Rider books were another series I loved growing up and I thought they would make great films if executed well. I was so disappointed by the film version of the first book, mainly due to the god awful (almost unforgiveable) ending that completely different from the book to try and include his love interest more in the film. I can also not understand why they changed the lead antagonist's nationality from Lebanese to American. I actually thought about 70% wasn't all that bad but it was certainly nowhere as thrilling as the book was and like with The Golden Compass, no sequel will be made and with good reason!
The last one is "Angels and Demons". While I don't hate this as much as the other two because it's actually a decent film in it's own right, but far too much was either cut or changed that made the book a really riveting read with unexpected plot twists. There were a lot of changes I didn't approve of such as keeping the fourth cardinal alive, not having the Cemerlengo immolate himself in front of the Vatican, having the assassin die in a completely different way and the sub-plot of the Pope being the Cemerlengo's biological father (a really surprise twist in the book). However, some of these are perhaps understandable with translating a book to feature. The most annoying change I felt was made was the exclusion of Maximillian Kohler from the film altogether. He was a really fascinating character and ended up being important for the revelation at the end, but instead the film rather half-heartedly fills in his role at the end with a side character with bearly a couple of minutes of screen time.
So there are my personal film adaptations I cringe over every time I think or read about, do you have any you'd like to share?