Bad Reviews - Do they really hurt your sales?

Yesterday I experienced my lowest review yet. 2 stars on Health and Safety.
At first, I felt kind of bad. I do tend to take things very personally. But, after reading the review, the reviewer had some very good points that I can use in both my future books and when I turn the novella into a full novel.

He found it hard to really get attached to the main character, Les. He wasn't overly impressed with the narrative, nor the development of how society came to be so stringent in its methods.

But what will potential buyers see? At the moment, there are only four reviews. Two five star, a four star and a two star. So far my sales haven't seemed to change for the worse. Perhaps they are just ignoring the poor review in light of the other better reviews.

I can only hope that more people review the book so I can get a better overall picture of how the majority of readers like it. Four reviews isn't a lot, especially since there have been well over a thousand downloads.

It would be nice if Amazon would allow a user to place a review through their kindle while reading or having completed their eBooks. It seems to me that once a user has finished a book, the last thing that they want to do is go back to the site to review it; unless they either loved it or hated it.

Please, do us indie authors a huge favor and review our books. We're competing against huge publishing companies that have giant marketing budgets for their books. We're competing against already well-established authors who have developed a following of loyal readers. It's not easy for an indie author to get their book out there and many times, even those of us with professionally edited works, our success is often left to luck.

I'm certain there are many great indie authors out there whose books are doing poorly and for no reason.

Review people! :)