I'm sorry this is such a long reply! But you hit a nerve!
A lot of movies and tv are taken from books and I never even knew that they were books, I just happened to find out later.
My faves are:
The Martian (probably one of the best books and movies IMO!)
Memoirs of a Geisha (both movie and book are different, but both SO worth it, I loved them both so much, and the movie instantly became one of my top movies when I watched it. It's so lavish, and beautiful, and colourful, and so amazingly brought to life the world that I read in the book.)
Wuthering Heights (every version, I loved the Tom Hardy version the most, but have a very soft spot for the Laurence Olivier version)
The Book of Negroes [*The title in Canada, has a different title in America "Someone Knows My Name"- sorry if the orginal title offends anyone] (this is the best book I've ever read. There was a 6 part tv series made in Canada for the CBC, and it was great! It was so good to see the characters and story brought to real life!)
War of the Worlds (The 2005 movie with Tom Cruise, he might get a lot of flack, but that movie is so good. It's obviously not exactly like the original book, but as a post-apocalyptic book/ tv/ movie lover, it scared me and was realistic at the same time. I read the book AFTER I saw the movie, and although the book is somewhat boring for the first half, it more than makes up for it in the second half.)
Forrest Gump (My favourite actor is Tom Hanks, so how can I not love this movie. I read the book many years after the movie came out, and although it is different, I still loved it a lot. I have to read the sequel, it's on my ereader, TBR.)
Jurassic Park (One of my favourite movies of all time. I read the book just within the past year or so, and it was just as fast paced and scary as the movie! Also read The Lost World which I also loved the movie for, but the book for this one was very different, but still a good read! I love Michael Crichton, ever since I realized that I could read sci-fi/ post-apocalyptic / scary *not necessarily horror, which I rarely read if it's strictly horror*, or science-y thrillers, which was only for the past 6-7 years. I never knew I could read that stuff lol, it never crossed my mind! I've also read and watched Sphere, and Andromeda Strain *and its sequel Andromeda Evolution, which would be a great movie sequel*. All great movies! And I LOOOOOOOVE love love Westoworld as a show [RIP!] but haven't read the book yet.)
The Secret Garden (now, a note, I haven't ever actually finished this book, because I tried reading it when I was young, and I couldn't finish because I was a kid and didn't have a good attention span for old-timey books. But I have it on my ereader to read in the future because I love the 1993 movie so much. It was so lovingly and beautifully made. It is a quality movie not just for kids, but for adults too. And in this category I'll also put A Little Princess, by the same author, but I only like the Shirley Temple movie from 1939 and titled THE Little Princess. Again, haven't read it yet, but the movie is so precious. I love Shirley, and she just makes the movie!)
Anne of Green Gables and Little House on the Prairie (Granted, I've only read Anne, but both were made into tv and movies so well. I am a very huge old tv nerd, and love my Little House! I have the books on my ereader to read. I also have all the sequels of Anne to read. The 80s Anne of Green Gables movies and Road To Avonlea Canadian tv series are some of my favourite shows of all time. The newer Anne/ Anne with an E series was so beautiful to watch, and fleshed out the characters so well, with a little more creative licence and a little more history that was in the book. And Little House clearly is different from the books, as I've learned from documentaries and reading about Laura Ingalls, but it was so lovingly made, and it was for tv, so I understand the differnces, especially for a show made in the 70s. I love both of these entities so much. They are very close to my heart.
Clearly, I'm a huge nerd, so I love Lord of the Rings, the Hobbit, and Game of Thrones, but I have never read any of the books. I feel as though I'm not a huge fantasy reader, but I love these 3 entities so much. I am not of the Harry Potter generation, but I do know that they were well made movies, as my sister is of that generation and loved them, as well as the Twilight series lol
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Some of my LEAST faves:
Interview with the Vampire (I LOVE the movie. It is also one of my most favorute movies, and made me a huge Brad Pitt fan. But... omg, the book. I couldn't finish it. It's so boring! I tried, TWICE to read it. I just couldn't do it. I'm glad other people like it, but how could the movie be so good when I couldn't get past a quarterway through the book! Please don't hate me LOL
The Passage [series] (It has to be my favourite sci-fi/ horror/ post-apocalptic book, or whatever it is under the genre of because it's kinda hard to box it in. It was such a wild ride, and I loved every minute of it, and then boom.. there's a tv show, and I was so excited for it.. and nope. Not good. They only took the one part of the story and just played up the scary part of it without touching any other parts of the story. it was so sad. It was exciting to see the characters in real life on the screen, but it was such a sad, sad version of the story that I loved so much.
Divergent [series] (I liked the movies. For YA stuff, I liked it, and it was watchable. I did read the books [pretty much the first sci-fi/ post-apocalyptic thing I read because it was already loaded on my ereader when I bought it used, so I thought, eh, what the heck.] and the books ended in a different way than the movies. I didn't like the end of the series because it wasn't the same as the movie, but all in all, it was meh. I realize now why I don't read much YA, and it's not to say that some of it isn't excellent, and that people read it, and I'm good with all people reading whatever they want, but it's just not as fully fleshed out as more adult-geared books can be, and I don't like the sometimes veering of into romance land.. I do not read romance LOL [but I don't poo-poo any books!]. I will probably just stick to watching the YA movies rather than reading them. Case in point, I very much loved the Hunger Games series of movies, but I'm not going to read them! Yes, ok, I have all of the books in hardcover, but that's just because I got them used for free lol)
The amount of books out there should set us up for good movies and tv for life, but sadly, Hollywood only makes it so that we get a small percentage of actually good tv and movies ever get okayed and then made well. So much sci-fi and fantasy is amazing as a book but they crap out when they make the tv series or movie. Plus there's stories from all over the world (written in English) that I've read and loved so much, but let's be honest, they're never going to be made into tv or movies, which is why we get the same stuff rehashed and remade and sequalled, and the same genre of tv show made over and over and over again, with the same tired plot. Personally, I cannot stand all these murder and crime shows. I read and watch tv/movies to escape. It's fine for other people, but how many of those shows can they possibly make?? To me, they're all the same with the same acting, the same story, with the same schtick. If Hollywood would look outside and greenlight things with more diversity, or more differing plot lines, or not always having to make a sequal of the biggest hits, maybe other stories would have a chance, but it's always the same old thing. They stick with what makes money. It's just business. I understand. But it's also very sad that I'll never see the books that I love made into good, **GOOD** shows or movies. (There's enough cut-rate, horribly made sci-fi on Netflix to last me a lifetime thank you LOL.. don't need anymore of that stuff either!) But I'm also thankful that I do have the Forrest Gumps and the Martians of the world. Thanks to the authors and big thanks to the people making the shows and the movies with some QUAILTY: all the Lord of the Rings, the War of the Worlds, the Crazy Rich Asians, the Jane Eyers, the Color Purples, the Handmaid's Tales, the Game of Thrones, the Harry Potters, the Last of the Mohicans, the Joy Luck Clubs, the Sense and Sensibilities of the world. I'm so grateful I live in a world where people take amazing stories and bring them to life with respect and love and joy.