Some book review websites follow the old rule: “if you can’t say anything nice, don’t say anything at all.” This is a good idea for a few reasons. One, if you are part of an affiliate program and get a percentage of the sale, you don’t want to discourage people from buying the book. (For this reason, I’m often skeptical of websites that tell you every book they review is the best thing ever written, then encourage you to click on their link to purchase the book.)
Two, if you’re a writer yourself and you give a fellow writer a bad review, they might retaliate and give you a bad review back. Well, I guess as they say, don’t dish it out if you can’t take it. Three: it’s mean to hurt other people’s feelings. It’s hard to write bad reviews for this reason, but I think if you keep all your criticisms constructive and don’t just be mean for the sake of being mean, it’s OK to write reviews that aren’t entirely positive.
Four: on the Judge John Hodgman podcast Episode 263 (yeah, it was over a year ago, I sure keep up with current events don’t I?), Mr. Hodgman once ruled that you should only give five star reviews because a writer’s livelihood depends on it. I’d like to focus on this last reason. Do writer’s livelihoods depend on good reviews? My impression is that most writers keep their day jobs, so I’ll say no. I mean, Hugo Award winner Kameron Hurley still hasn’t quit her day job, so what chance do us lesser writers have of ever quitting ours? I’d highly recommend all writers follow her blog because she discusses the reality of the writing business, and the reality is most writers make less than minimum wage off of their writing. True, some people do make a living off of writing, but they’re the 1% who got lucky. And those mega-stars can handle getting bad reviews without losing their livelihoods.
Nobody (not even established publishers) can predict how well any given novel will sell. Litrejections.com has a list of best sellers that were originally rejected. For example, Harry Potter was rejected 12 times before going on to make its author a billionaire, but there are many more examples. Some best sellers were initially rejected over 100 times. Jack London received 600 rejections before publishing a single story. Which goes to show that success as a writer depends on persistence in the face of rejection. If you can’t handle receiving a rejection or a bad review, you’ll probably not end up with a career as a writer.
You might have a best seller one year, then never have another best seller again. That’s just how this business works. Why does one book about teenage vampire romance become a best seller while another book about teenage vampire romance wallows in obscurity? Really, success in the writing business is mostly based on luck. It’s kind of like playing the lottery. I dunno, maybe that one bad review you got that one time prevented you from becoming the next J.K. Rowling, but I suspect it doesn’t really matter in the overall scheme of things. When you fail to win the lottery, how can you really blame anyone for that?
Besides, if you applied this rule to other professions and give nothing but five star reviews to plumbers, electricians, tree trimmers, etc. you might end up steering people away from good businesses by giving all the bad businesses good reviews. If a customer service representative is rude to you and dismisses your concerns should you give them a perfect rating because their livelihood depends on it? Giving nothing but perfect reviews defeats the whole purpose of reviews. If everybody gets five stars every time, then it becomes meaningless. What Judge John Hodgman is proposing is akin to participation trophies.
Also, they say there’s no such thing as bad publicity. Just like it’s better to have bad credit than no credit (I know this from personal experience having worked in the credit card industry and being someone who had no credit for a long time), it’s better to have bad reviews than no reviews. A book without any reviews shows up at the bottom of search results, which is as good as not existing in the first place. Also, as a writer myself, I like to receive constructive criticism. If you didn’t like my book, I’d prefer you tell me why so I can improve. If you don’t leave a review at all, or leave a good review you think the book didn’t deserve, I can’t improve as a writer.
Obviously, I don’t want to defend negative reviews which aren’t constructive. Simply saying, “this book sucks” doesn’t help anybody. But, as I state above, if you say why you didn’t like a book, it could help the author improve. It won’t always help the author improve though. You can’t please everybody. One person might not like a book because it has too much sex, violence, or cursing, for example, while another person doesn’t like the same book because it didn’t have enough sex, violence or cursing. But I think it’s at least helpful to the author to know why someone didn’t like a particular book.
Bad reviews are also useful for fellow readers. I’ve had people thank me for writing bad reviews because I saved them from spending their money on a book they wouldn’t have liked. Again, since everyone has different tastes, saying something like “this book was poorly written” doesn’t help fellow readers know if they’ll personally like a book or not since they don’t know what you mean by “poorly written”, but pointing out that a historical novel isn’t historically accurate can be helpful to people who care about such things.
Also some website will make recommendations to you based on how you rate similar products. I used to give good ratings to movies on Netflix I didn’t personally like because I was rating based on the quality of the movie, not on whether I liked it or not. I soon realized if I rated movies I didn’t like favorably, I’d end up getting recommendations that didn’t work for me. There’s nothing wrong with people giving low ratings to books they don’t like for the same reason. Writers shouldn’t take it personally. We all know everyone has different tastes. Complaining about a bad review is kind of like a chef complaining about a customer not liking olives. You can make the best olive tapenade of all time, but if a customer doesn’t like olives, they don’t like olives.