Stephen King, from On Writing:
Amateurs sit and wait for inspiration to come, the rest of us just get up and go to work.
Also from On Writing:
But it’s writing, damn it, not washing the car or putting on eyeliner. If you can take it seriously, we can do business. If you can’t or won’t, it’s time for you to close the book and do something else.
Wash the car, maybe.”