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.
Lol, the book is referenced in an Italian indie movie, “Santa Maradona”: the costumer of a bookstore asks to a character (who is NOT part of the bookstore staff) where she can find a book with a mix’n’match title between this one and Stefano Benni’s “The Company of the Celestines”. He gently answer that she may have confounded the two books: Benni’s book is slip-mainstream “and we don’t sell mainstream-ish books which appeal the masses”, while this one “is a nutty new age book full of poppycockeries and we don’t sell this kind of trash”. Then, with passive-aggressive kindness, he invites the costumer to go away. (She is then approacjed by an actual bookstore staff memeber and insults him).