There are books I started and did not finish that I do not remember. However, there a few that I finished but hated. The worst was:

Reverie - this was a lgbt book club thing in Libby. The protagonist was a whiny incapable teen that never redeemed themself. I kept thinking it would get better and it never did. Things resolved because magic, so poor/lazy writing.

Mine is "the catcher in the rye".

The main character is insufferable and not enough bad things happened to him to make it worth reading the book.

The Rings Of Saturn

Was chosen by my Community College English professor and it was the most mind numbing thing I've ever had to read. It was translated from German, so there are multi-page, run-on sentences that haunt me till this day.

A Heartbreaking Work of Staggering Genius by Dave Eggers. If you could distill pure insufferable smugness into a liquid, this was him squirting it into your mouth while you’re not paying attention and laughing at you while you sputter and gag.

I don't even remember the title, but it was written by Clive Cussler.

It was the dullest, most stereotypical adventure book with the bog standard protagonist and plot, with no interesting twist or unexpected event at all.

A book called The Night by a Venezuelan author.

I feel a bit bad saying this because there are definitely worse books but this one stuck with me as the premise sounded really interesting but the book was nothing like it.

There is a review on goodreads that sums it up pretty nicely.

Literature about literature, books about books, literature about books, books about literature, literature about literature, books about books, ...

A collection of short stories by Harlan Ellison.

It was an absolutely insufferable read. Specifically, his foreword between each story.

Game of thrones, for me. Made for a good basis for a show. Fucking terribly dull to read.