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.

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.

The Alchemist, I had to read it for a community college class. It's probably the most predictable book I've ever read, but not in an entertaining way. Just painfully boring.

I read Siddhartha for highschool a couple years before, I would say that the books are almost identical, except I liked Siddhartha more.

You want a book with similar themes but actually amazing? The wizard of Earthsea.

I know the books aren't literally the same. But the vibes feel very similar. I want to say they have very similar structure, but my memory doesn't work that great.

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, ...

I am not sure about 'ever' (I am old and have been reading for over 4 decades now), but a book I hate-read recently was Foucault's pendulum by Umberto Eco. It is meant to be a satire on conspiracy theories and as such it is still a relevant book after 35 years or so. However, the point of satire is to get to the point eventually, preferably within 500 pages. It was pompously written and sometimes felt like a showcase of 'look how much I know!'.

The Great Gatsby.

I've read a lot of books, but that one I literally remember nothing about. Not a quote, not a character, not the plot... All I remember is the cover was some weird abstract art piece with creepy eyes, my brain purged everything else about it book. Probably for my own sanity.

The old man and the sea. I learned to hate reading because of assigned books in school and this was the one that drove that hatred most. At times in my childhood I enjoyed reading a couple of novels, but assigned books absolutely destroyed any interest I had. Also having religious cult like parents that always had something stupid to say about reading had a major impact.

The Casual Vacancy

I forced myself to finish it at the time, but I hated every single moment. They were all bad people and I had zero sympathy for any of the kids or adults, except for the one girl who died at the end. Obligatory Rowling can jump off a cliff too.

A collection of short stories by Harlan Ellison.

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

I haven't read a whole lot, but so far: Madame Bovary. We had to read it in high school, because it was culturally significant and because it caused a large amount of controversy when it came out due to its subject matter. When I was reading it though, it felt like I was reading a literary version of every TV soap opera ever. It was a slog to get through and I was bored and annoyed throughout.

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

The Pearl by John Steinbeck. Its technically a novella but still. Hated it.

Probably Don Quixote. It started off really well, but it devolved towards the end into this long-unending self-referential rant full of name-drops and exposition, and I could barely follow any of it and pushing through that was a huge chore.

I later learned I had read a bad translation, and that there is one good translation out there I should try, but the whole thing has left a bad taste in my mouth and I don't want to go anywhere near that book again.

I tried reading two different series from Stephen R. Donaldson, and it seemed to me he was somehow unable to write a book without a horrific rape. I just stopped reading the first book in each case because I felt like they were salacious and hateful.

Art of War in the Middle Ages. Just fucking interminable.

https://www.gutenberg.org/cache/epub/44308/pg44308-images.html

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.

Silas Marner has to be the most boring book I've ever attempted to read.

Didn't help that it was an assignment for school, but it also didn't help that it's literally one of the most boringly written books ever.