"Most people live haphazard lives subject to the varying winds of fortune. Many are forced by the situation in which they were born and the necessity of earning a living to keep to a straight and narrow road in which there is o possibility of turning to the right or to the left. Upon these the pattern is imposed. Life itself has forced it on them. But the artist is in a privileged position. The artist can within certain limits make what he likes of his life. In other callings, in medicine for instance or the law, you are free to choose whether you will adopt them or not, but having chosen, you are free no longer. You are bound by the rules of your profession; a standard of conduct is imposed upon you. The pattern is predetermined. It is only the artist, and maybe the criminal, who can make his own." W. Somerset Maugham, "The Summing Up"
I came across this quote recently and it both struck me and stuck with me.
...partially because it's true, partially because it's somewhat sad.