Good Reviews are Better Than Kind Reviews
Are you afraid to leave a bad review for stories by authors you know? Most people are. When a reader knows an author personally, (or has a professional relationship with one) there's a commendable desire to protect that bond. What friend would want to hurt someone's chances of success? What professional would want to be disrespectful? No one wants to be rude, nasty, or mean. Better to avoid hurting feelings or worse, setting the stage for retaliatory action. As the saying goes, "If you can't say something nice, don't say anything." Right?
Wrong. When it comes to leaving reviews of published works, the saying is wrong. Reviews are too important a part of the reader-writer relationship to be reduced to platitudes.
If you've read a published work -- especially one by an unknown author-- and you have a strong opinion about it, then I would say you not only have a right to review it, you have a duty to do so. A duty to fellow readers.
(Note: this is an example of rhetorical hyperbole. If you don't want to write reviews, don't. If you are uncomfortable expressing negativity, don't. If you don't finish a book, don't review it. If you don't like an author personally, don't review their books... you get the picture, right?)
I'm only asking that you don't misinterpret a review's prime purpose. The focus on good versus bad obscures the point of reviewing and conflates it with another important interaction between reader and writer: critiquing.
Reviewing isn't about being kind or handing out warm fuzzies or being mean or rude. Anything an author has published is up for public consumption. Reviewing is a public service. Critiquing is something else again. (Another post, someday.)
The reviewer's role is this: to inform a prospective reader about the work. That's all. Only one person's needs should be considered: the reader's. Not the writer, not even the reviewer. A review by its very nature is an opinion piece, but the essence should be objective evaluation, not a quality judgment.
I've been professionally recommending books for 19 years. I've sold plenty of books I loathe with a clear conscience for just as long. My opinion counts, but I have no right to pass sentence on a book's True Worth. What I hate, others may adore. A reviewer's role is to inform.
An example: I despise Terry Goodkind's Wizard's First Rule. If I rated it, however, the star rating would be 3. A review would go into great detail about what I dislike. (And now I feel the urge to head over to Goodreads...no. Must. Resist. Temptation.) Anyway, my evaluation of the book's appeal to certain readers, based on certain preferences, is 5 stars. My personal opinion is zero stars. In a review, I can explain all that. Oh, if I had a dollar for every time I sold a book after saying, "I hate this one, but if you liked XY&Z, you should give it a look..."
Tastes differ. Tolerances differ. Interests differ. Your review can be a litany of complaints, and end up intriguing a prospective reader. Your most-hated flavor is someone else's favorite. Your idea of an insomnia cure is someone else's idea of a perfect read. As long as any vitriol is wiped off before posting, you should be honest about any perceived negatives of plot, character etc. Be honest about mechanical and structural problems as well. You don't have to dwell on them. A reader can judge the details by a glance through the free online sample or riffle through the first ten pages. Just don't pretend they aren't there, or expect your credibility to plummet.
What about the writer's feelings? Hm. That's a toughie. If you're concerned about how a friend will respond to a review, then run it past them instead of posting it. If objections, protests, or tears flow, then call it a private critique, (another important act of selfless service on the part of readers!) offer warm fuzzies, and of course honor the friend's wishes regarding its publication.
Still. The point to keep in mind is that a reader's real responsibility is to other readers. First and only. Lying to the Emperor about his state of undress helps no one, least of all the Emperor (or Empress)
A side note: don't obsess about stars. A star rating is nothing more than an artificially-colored, flavorless cherry on the rich fudge sundae of a real review. Make your points about a story in detail, using all your words. A writer who is a reader is a reviewer in the making.
Let's wrap up this soapbox screed on a cheerful note. Bad ratings/reviews do not hurt a book's chances nearly as much as no response at all. Obscurity is the real enemy. Bad reviews (or middle-of-the-road ones) do not deter readers, but too many good ones can. When a title with more than 5 reviews has none under 4 stars, it raises my suspicions about the reviewer's motives. Even the classics get panned. War & Peace has its detractors. So does Twilight. I could go on. I won't. That's enough of that.