At a recent writers conference, I heard this as well: No one else can write the story God has given YOU to write. (Paraphrased)
Whether you are a writer, an engineer, a software programmer, a counselor, a doctor, or a dog-catcher - you have a unique set of skills and abilities. There may be millions who do what you do, but no one can do it exactly as you do. No one brings your combination of life experiences and personality to the task.
For me, that changes the way I view my job (all my jobs: my full-time, HR Manager job, my author job, and my roles as a mother, wife, and member of my church...to name a few). God has given me all that I need to accomplish His purpose for me in each particular role. What I lack, He gladly supplies when I ask in prayer.
It also changes the way I see the art I create, particularly through my writing. Writing is not something I do to entertain myself in my spare time. It isn't something I do for fame or for money (thankfully, because if it was, I'd be terribly disappointed). It is a calling from God to tell stories, modern-day parables, that point the reader to Him.
The purpose of God gifting us with knowledge, skills, and abilities is not our achievement, but the glory of God.
I love hearing from people about their calling. What has God gifted you to do and how are you using it for His glory?