Do comic books count? If they do, my vote for a horrible movie made from a book that I absolutely love goes to Keanu Reeves' Constantine from 2005, which was an adaptation of the DC Comics Hellblazer.

I was disappointed because the story made such a heavy departure from the source material. It lost the edgy, dangerous, horror vibe of the comics and became a tame and kinda goofy Hollywood movie. And as much as I love Keanu Reeves (I love him as John Wick), he was also miscast as the lead here. He seemed too clean-cut and GQ-looking to be John Constantine. Plus, he didn't have the rough, devil may care attitude of a terminally ill exorcist who has been damned to hell, which is what made the original comic book character so interesting.

I feel like with this movie, the people behind it were either too afraid to deviate from the formula or too scared to offend so they made safe choices. But the thing is, if that's what they were gonna do anyways, then they shouldn't have chosen a comic book like Hellblazer to adapt, in the first place.