I'm fine with book reviews that I don't agree with or aren't informative, etc as it all comes down to personal opinion and not everyone is good at articulating why they do or don't like a book but there's this one review on Goodreads that just triggered me when I read it years ago.
The reviewer gives his reasons for disliking the book then says "please stop writing books like these". I'm probably overreacting but those words never fail to annoy me. I'm not arrogant enough to think my taste in books is superior to everyone else or that authors should only write books that please me.
More importantly if the author had listened to that review many other readers would have been robbed of a book and series that they enjoyed. No matter how bad a book is, there's going to be someone who like's it and that person should not be robbed of the joy of reading just because the reviewer hated the book.