Why I don't review books I don't like

I don't post negative reviews of books.  Of course, there are books I don't like!  There are some books that are just not good by any standard and there are others that just are not to my taste.  And, sometimes, I read these books.  But I don't review them.  There are several reasons:

1. I usually don't finish them.  I used to try to finish almost every book I started.  But there are so many books that I really enjoy that I decided not to do this anymore. I could quit reading after 10 pages, 20 pages, 100 pages or wherever.  It's not fair to review a book I didn't finish.
2. As a writer myself, I know it's a lot of work to write a book! While I don't mind constructive criticism sent to me privately (in fact, such criticism is valuable) I wouldn't like to read negative reviews on a public forum.  I doubt any author would.  So, I don't post them.  
3. I don't like writing negative reviews.
4. I am not a professional book reviewer.  Big book review magazines have some sort of duty or obligation to review new books that will interest their readers, regardless of whether the book is good or bad.  I'm just writing for you and me and most of what I review is not major new releases.

 On another note, I've changed the format for my book reviews.  Look at the last few of my book reviews and let me know what you think.