As a follow up to knowing yourself enough to make good purchasing decisions for yourself (or at least most of the time). I was reminded of this reading the Amazon reviews for The Totally Geeky Guide to The Princess Bride by MaryAnn Johanson. Reviews included the following notes:
*I thought it would be an insider's guide rather than a geeky guide.
*I wasn't that familiar with the movie before I read the book, so I didn't totally get it.
*The author liked the movie for different reasons than me.
Now, to clarify, all of these are totally valid reasons for not feeling the book was a good fit for you. And I am a little torn, because I certainly feel that this helps me understand the biases that led each of these people to the grade they gave. But really, all they tell me is that you didn't read the description before you bought it. (If the description was misleading, this would be helpful, but really, it is not.)
And I realize these are your thoughts, you have a right to them. They are your expressions of your feeling about your purchase. But I find such reviews as annoying as, "I like everything this author has ever written!" because, while possibly true that doesn't give me any information about the product in question that helps me make and informed decision.