I’ll go with the low-hanging fruit: Mein Kampf. I’ve read it, cover to cover. As a piece of propaganda, it’s good. As an example of good writing? Absolutely not (though I will admit I have only read it in translation). Oh, and the whole fascist, racist, and generally shitty worldview of the author that he infuses into the text. And the fact that the author is literally Hitler. You 5-star that book? You’re a Nazi. Period. And as a Jewish person, I don’t look too kindly on them.
In 2013, I went on a date with a guy who told me his favorite book of all time was The Art of the Deal. He went on and on about what a work of genius it was and how it had changed his whole philosophy of business and made him a success. I went so far as to read it before I understood what an absolute loser he was. Lesson learned.