The post below is by James Reed, Chairman of REED recruitment; the sentiment that a complaint is a positive gesture makes real sense. It is all too easy to just disengage with a product or service if you are underwhelmed by an experience for some reason.

As the recipient of negative feedback it can sometimes feel like you're being heckled at an away sports match, where the correct response is to block out the noise and concentrate on the job in front of you. This can be particularly true when the service in question has been delivered by you personally (like, say, professional services for example), when the feedback can potentially affect your career.

However, for a client to give feedback means they have invested their time in your business and it is very important that their concerns are taken seriously. Their investment requires reciprocation and represents a chance to build on their gesture of friendship to deepen your relationship. 

Viewing negative feedback through James Reed's lens is difficult and may need more humility than we want to require of ourselves in the workplace but is unquestionably the best possible approach.