Battlefield Earth was my favorite book as a young teenager. Ignoring everything else about the author (which I didn't know at the time), I thought the book was brilliant (especially the first half). It touched my imagination in a way no other book had before, and I must have read it about a dozen times.

I seem to recall the book cover saying that a major motion picture was coming out soon, but I guess time is relative. For me it was about eighteen years (which was more than half my life at the time) before the movie actually came out, and that seemed like an eternity.

I wish I could say it was worth the wait. The movie was horrible -- it had bad acting, a bad script, and couldn't carry the book in only two hours.

It currently has a 3% tomatometer score at Rotten Tomatoes and a 2.5/10 at IMDB. The movie also won Worst Picture of the Decade at the 2010 Razzie Awards.

I hated the two made for TV Terry Pratchett adaptations of Colour of Magic and Going Postal. Like, they pissed me off so hard I couldn't sleep. Particularly Going Postal (my favorite Pratchett book), they couldn't have missed the point of it any harder even if they tried.

American Gods

The first season of the TV series is a banger, but the subsequent seasons suffer from a decline in quality. Also, the series finale is just so disappointing compared to the ending of Gaiman's novel.

The Firm

Misery

American Gods

I am legend

The Wrinkle in Time movie, think Oprah was in it. Haven't seen it, heard it's horrendous.

I don't know if it's the worst, but I am very disappointed with the movie adaptation of Mortal Engines. The series has such a rich world to explore and very good plot points that would have been amazing to see on the big screen.

The movie ruined any possibility to see a sequel or even a reboot in a very long time (similar to what happened with His Dark Materials), although the fandom now prefers that if there is another attempt at an adaptation it has to be a TV series and animated.

Are you referring to the Golden Compass movie or series? The movie was trash, but I thought the TV series they've been doing has been pretty good.

For me Ender's game was a massive disappointment. I also didn't like the hobbit trilogy. Huge fan of LOTR, but the hobbit movies just didn't do it for me.