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.
I don’t think it’s that the book is really so bad, it’s more that it was a mediocre book that was extremely popular. Same with all the Colleen Hoover stuff. I thought ready player one was ok, but if someone thinks it’s a 5/5 then I’m assuming they really don’t read much…