Churchill said

Winston Churchill once said: Criticism may not be agreeable, but it is necessary. It fulfills the same function as pain in the human body. It calls attention to an unhealthy state of things.

Regardless of where you work or who you work for, being able to take criticism is part of the job description. Whether you're getting feedback from your boss or a client, having a proper perspective on criticism and a sound understanding of how to use it effetively is important.