Here’s a great Mark Twain quote about finding out what your "work" is and the dangers of doing someone else’s "work."
What work I have done I have done because it has been play. If it had been work I shouldn’t have done it. Who was it who said, "Blessed is the man who has found his work"? Whoever it was he had the right idea in his mind. Mark you, he says his work–not somebody else’s work. The work that is really a man’s own work is play and not work at all. Cursed is the man who has found some other man’s work and cannot lose it. When we talk about the great workers of the world we really mean the great players of the world. The fellows who groan and sweat under the weary load of toil that they bear never can hope to do anything great. How can they when their souls are in a ferment of revolt against the employment of their hands and brains? The product of slavery, intellectual or physical, can never be great.