This is a great quote from the book: Creating a Life Worth Living, by Carol Lloyd.
There is a vitality, a life force, a quickening which is translated through you into action, and because there is only one of you in all time, this expression in unique. If you block it, it will never exist through any other medium. It will be lost. The world will not have it. It is not your business to determine how good it is, nor how valuable it is, nor how it compares with other expressions. It is your business to keep it yours clearly and directly, to keep the channel open.
You do not even have to believe in yourself or your work. You have to keep open and aware directly to the urges that motivate you. Keep the channel open. There is no satisfaction whatever at any time. There is only a queer, divine dissatisfaction, a blessed unrest that keeps us marching and makes us more alive.
– Martha Graham to Agnes DeMille