Think of it this way: A strong response to a complaint can change someone's perception of your business and cause them to tell the community how responsive you are.
When a consumer doesn't say anything to you, you are powerless to rectify a situation. That same customer is going to share their poor experience with their friends and associates. By welcoming ratings (both good and bad), you set yourself up with a mechanism to reply to public comments.
On our website, the typical consumer likes to view not only good ratings but bad ones as well-primarily to see how a business reacted to the complaint. Nobody expects a business to be perfect, but they do expect accountability. This may mean rectifying a situation before it escalates or just acknowledging and apologizing for a problem.