I have come to absolutely hate the obvious self-inserts of authors, when done in a way that looks like a day dream of a teenager with power fantasies in puberty. Or when the whole story caters to an audience that loves to do that as well. All these isekai-level999-cheat-skill-harem mangas that have been popping up in the last years are what I have in mind specifically, but I have also seen this in actual books. Especially books with teenagers as a target audience, they tend to either over power the protagonist, giving him ridiculous plot armor, while also trying to make him look imperfect so that all the "misunderstood" teens in the world can see themselves in them, and so on. I saw this in Harry Potter for instance. The author made it a point to call Harry a regular normal boy all the time, when in fact nothing was ever regular about him. And then he suddenly got rich, was famous, but still tragically misunderstood, magically talented in sports, the favourite of the teachers that matter, and somehow still part of the uncool clique. Riight.
It's all so terribly obvious and totally boring. Every teenager had always had these day dreams where they suddenly are the center of the world, and have these awesome powers and then get either all the girls or that one girl that really matters. Every teenager into games or fantasy stuff, always hade these ideas about what they would do when they would be personally in that game or this story, but with this one super cool power. It's normal, it's bland, it's common place. And I really don't need to read a story of somebody else doing the exact same thing.
Be it original OR fanfiction: BAD UNFAIR ENDING for the GOOD GUY(S). Which is also visibly ENJOYED by the freaking AUTHOR themselves. One such currently in-my-head example being: "That Epilogue of the Good Guy having a Good Ending? That MIGHT or MIGHT NOT be just the Good Guy's PRE-DEATH DELIRIUM." UUUGGGHHH..!!!
I hate the books that goes cheesy or corny or hopeless romantic or whatever it called. Then, a book with the female as the weakest creature, they're slaved or forced to do what they didn't like to and do nothing to change their life.
I typically find that dystopia is incredibly predictable, which is why I did not enjoy The Hunger Games triology when it first came out, not to mention countless other stories of similar nature. Occasionally there is a plot twist, however most are very basic and you can predict the main plot points with just a quick skim.
I hate books that seem like novels, but are actually thinly veiled political screeds. The Fountainhead would be the best known example, but there's several of them out there. At least Jonathan Swift had the decency to keep A Modest Proposal as a short essay. I dislike books that deliver their climax early and the rest of the book is simply waiting out the inevitable. I've just finished 2 Sci-fi books like that; Nightfall by Isaac Asimov and Robert Silverberg and The Forge of God by Greg Bear. I really hate non-fiction books that should have been a 10 page article, bulked up with barely related material to publish it as a book.
The book Lucky by Alice Sebold written in 1999 is based on a true story... The author who wrote The Lovely Bones tells of how she was raped in college, then the trial afterwards and how she overcame all that happened to her... Let me tell you after I finished reading this book I kept my legs crossed for 2 years... It really freaked me out.
Boring books. Good blurb, but bad writing. I like comics, but really love boring old text in novels. Much fun if they're really well written. I don't mind manga if the art is clean. But most of the manga I've seen has really nice artwork anyway. I think it's formatting of text that can put me off in comics. Having a whole page stuffed into one speech bubble does not look good. Especially when there's not enough space for all the letters.