My favorite is this review of Scalzi's own novel Red Shirts, which actually uses the word "onanistic":
This is an onanistic shallow and very disappointing book. Little or no character development. What should have been an interesting short story based on a somewhat interesting conceit has been puffed out to novel length and suffers hugely from the increased exposure. Don’t waste your time or money… The only interesting element was the coda about writer’s block which, I fear, seems to be very close to home for him as reflected in recent work.
Also, this review of Neil Gaiman's classic The Graveyard Book reminds us that some.reviewers.just.don't.get.it:
I am amazed that this book has won awards — I wonder about the judges who voted for this completely unsuitable book. The book revolves around graveyards, murder, ghosts and a child called Nobody. Being called nobody certainly would not improve self esteem. This is a horrible, highly negative book.
One of my goals in 2014 is to take the time to leave more reviews of works I love (not just books, but restaurants, shops, etc.).
It's one of the best and easiest ways to support someone's success. If you haven't yet reviewed The 7 Secrets of the Prolific I would be grateful if you would do so. (Use this link.) Even a 1-2 line review is fine--and in some ways better than a long one.
And, yes, I do leave the occasional negative review, but only if the product or business in question is truly dreadful. Here's an example.