In small business and in life, if you are doing anything at all (instead of simply stagnating), then you will inevitably have people criticize you. People that take action and build things of any importance are constantly criticized. You can either let the criticism crush you or you can deal with it.
Tim Ferris has a fantastic post about how Dr. Martin Luther King handled criticism. In his famous “Letter from a Birmingham City Jail”, Dr. King notes:
While confined here in the Birmingham city jail, I came across your recent statement calling my present activities “unwise and untimely.” Seldom do I pause to answer criticism of my work and ideas. If I sought to answer all the criticisms that cross my desk, my secretaries would have little time for anything other than such correspondence in the course of the day, and I would have no time for constructive work. But since I feel that you are men of genuine good will and that your criticisms are sincerely set forth, I want to try to answer your statements in what I hope will be patient and reasonable terms.
Note that Dr. King was in jail and under the strain of criticism few humans are likely to endure. The full letter is long but definitely worth a read. He not only dismisses most criticism, the criticism he deems as fair he engages vigorously and makes his case passionately.
Business and Life Lesson: Most criticism can be dismissed, the valid criticism (typically from people whom you respect) should be listened to and acknowledged. Don’t let critics prevent you from doing what you deem necessary to live the life you want to live.