But if you can handle the bad reviews and occasional trolls, without falling into a deep depression that requires a healthy dose of Prozac, I find reading reviews to be very informative and helpful in discovering my strengths and weaknesses as an author. I won't agree with everything left in a review, and that's okay because I understand you can't please everyone and you are writing to please yourself (it's your book!), but if there is a running theme throughout negative reviews on a book, then you can the identify weak spots, and vice versus for the positive reviews. This knowledge can help me improve my craft and become a better storyteller.
Did you know, that on average, only 1 review is left for every 100 sales on Amazon? So, seriously, if you like a book, PLEASE LEAVE A NICE REVIEW! That is all.