For me, saying that a book is good or bad isn't enough. I feel obliged to say why. Possibly because I majored in English literature and possibly because giving a superficial 'yay' or 'nay' isn't my thing.
I recently read a novel where the main character was an elderly knight but the cover indicated a much younger knight. I felt that it was a discrepancy because, let's be honest a lot of people can pick up a book based on its cover. If the cover is misleading, many may feel cheated.
Check out my book reviews page for the genres I've read and I'm currently reading.