As authors we have to understand that it's not a requirement of a reader to leave a review.
Think about it for a minute. Put yourself in the readers place. You have a limited "entertainment" budget for the month. Maybe you buy a book to read for your enjoyment. You aren't a writer. You simply want to leave reality for an hour or so and get lost in a book. Why are you then expected to feel like you are back in highschool or college and get out your pen and paper and write and essay on it. Ok how did I feel when I read the book? How did the character make me feel? OMG was there any typos in this book? Should I mention the typo I saw in this book? Ok now their nice little get away for an hour or so turned into a stressful not fun event.
And as authors we like to think it's just a sentence or two. It would only take them a minute or two to write it down. But why should they? Every time you go to say Wal-mart and buy something do you run to the computer and post a review about it. I bought a dvd. After my kids watched it did we run online and post a review about it? No. After we played a board game did we run online and go to Amazon and post how much we liked it? No? Did we try and contact the creator of the game and tell them how much we liked it? LOL No. I'm betting that you don't either.
So the anger we feel as authors for the lack of reviews we get should be turned into thankfulness that somebody took their time and money to buy our book and we should appreciate them for that and not have anger issues about not getting a review for it. Just my two cents