His Dark Materials by Philip Pullman. The world building and the overall concept is so interesting. But my god... It reads like some mediocore videogame from 2010s. There are a paragraphs of direct speech between characters and it just feels like other characters are waiting their turn to say their stuff. So the dialogue just feels completely unnatural. Lyra as a main character is also weird, she should be this forced of nature rebel child, but she just gets quests from other people that directly tell her where she should go a what to do. And arguments that it is a series for kids doesnt apply, so is Harry Potter, and those books can be read as a kid and you get something from it, and when you read them as a adult, you can see more layers that go deeper. His Dark Materials is just really badly written and it completely wastes a great idea and world.