I have two. The Ritual and Drowning.
The Ritual is pure smut. 61 chapters and every one contains a graphic, demeaning sex scene. I’m convinced the author was an adult film screenwriter and decided to try their hand at writing a novel. There isn’t a single likable character in this book.
Drowning isn’t a great work of literature. I felt that the characters were very two-dimensional. I hated how naive the author made the protagonist. It made me have a lack of sympathy for her. The ending was series finale of Dexter bad.
OK, I have an extremely controversial one:
The Stand by Stephen King
I know, I know. It wasn’t the original but his expanded version. And I found it so unbelievably ponderous with King belaboring every point. After about 200-250 pages, and realizing I was nowhere close to getting into the actual heart of the story, I gave up.