Reviews, whether positive or negative, lay a great impact on the reputation of an organization. Customers who are new to your website will always evaluate the previous reviews already posted on your website and then base their opinion or action upon those reviews.
Customer, who had an unsatisfying experience with your organization, will definitely express that in terms of a review on your website. So, keep this in mind that you should always revert to such displeased customers and please them so that they will again offer a review in a positive manner. Moreover, positive reviews are valuable only if others can actually see them, thus such reviews should always be promoted and displayed.