Asklemmy

The Hobbit. Probably not the worst movies with not the worst bastardisation (that'd be The Dark Tower for me), but I simply can't wrap my mind around the overbloated monstrosity that the Hobbit TRILOGY is. Like why would anyone do this, it felt like it's in the bag, they got Peter Jackson, they already made LotR to great success, why do we suddenly need wacky wheels with cartoon CG goblins in 48 FPS for some reason... It doesn't even match neither the tone of the book nor the tone of LotR movies.

"I Am Legend" has been made into 3 or more movies, none of which have anything like the book's ending.

The Last Man on Earth (1964) is dull and misses the point almost entirely, but almost manages the title line. Not quite.

The Omega Man (1971) is exciting and misses the point even further.

I Am Legend (2007) almost gets it. The vampires are competent. Will Smith's smarter than Neville of the book, but crazier. But then both endings fail to treat the vampires as a society.

Not a classic book, but Artemis Fowl. Disney managed to confuse fans of the books and newcomers to the series alike by adding a McGuffin that was unnecessary, bringing the antagonist from the second book into the movie on the first book, and mangling the relations between the two main protagonists beyond recognition.

Because no one is going with the classic, I can mention Eragon.

I, robot.

World War Z. Not a classic book, but still...Wtf.

Easily "World War Z." What an utter waste of the source material.

Possibly controversial, but I thought the movie version of Hitchhiker's Guide to the Galaxy was a huge disappointment.

Luckily there's the radio series, books, TV show, comic, play, and game to get me through :-)

The many adaptations of the Iliad, none of them is gay enough.

Starship troopers. I say this not because the movie is bad (it's not, I think it's exactly what it meant to be and did it well), but that the movie and the book are thematically opposites. The book is very pro military authoritarian. The movie is a satire of that.

"Do Androids Dream of Eletric Sheep"

You'll probably recognize it as Blade Runner but the film took so much liberty the author allowed a good friend to write three sequels in order to harmonize the book with the movie.

Also "Starship Troopers".

No one appears to have yet mentioned Forrest Gump. In the book he was a chess grandmaster who wrestled professionally and was an astronaut. Also, the book sucks.

Not a classics, but:

• American Gods: they made unnecessary changes and introduced unnecessary filler plotlines until it felt like a drag to watch. The book already explored social issues, but the showrunners decided to dial it up to 100 and spoonfeed it to the audience at the expense of the actual plot.
• Ready Player One: they dumbed down the whole thing about hunting keys and portals, removed tons of important worldbuilding details, made pointless changes that ruined the spirit of the books. They should have made it into a series instead of a movie.

I would say Rings of Power, then again it has basically nothing to do with any books and seems to be based on bad fan fiction.

The foundation series by apple is pretty bad.

How bad? The absolute best part is a part not present at all in the books (the Cleons). Everything related to the book is bastardised, imo.

Not a classic for most people but zoomers will agree that Percy Jackson and the lightning thief was a tragedy.

The Dark Tower. I don't get what that was, the books were far richer.

Oh, another one I just thought of - How to Train Your Dragon.

The movies are fine, but they are so completely different from the books in almost every respect that it's barely worth giving them the same name.

The books are absolutely brilliant, especially the further you get into them. Would love to see them developed as a TV series that stuck to the style and messages of the books. Would likely need about 10 seasons though!

The Gunslinger. It was supposed to be more of a continuation of the books but it just sucked all around.

I'm going to flip the spirit of the question and say that Michael Crichton's Timeline movie adaptation is so bad that it falls into so bad it's good territory. I own it on bluray, and we watch it at least once a year.

Any visual media that you've seen after you've read the source book. A better way to look at it. It is which movie was better or as good than its book.

Jurassic Park was a better movie than the book. The Martian the movie was as good as the book.

Eragon. They really fucked up so much about the book!

Dune. The Wheel of Time series on Prime.

"The NeverEnding Story" should never have been made into a movie. It's almost ironic. Every time a child watches the movie instead of reading the book, that's an opportunity lost.

I have to imagine that Lawnmower Man is in the running. Talk about having nothing at all to do with the 'book' , (well, short story anyway).