"One writes out of one thing only -- one's own experience. Everything depends on how relentlessly one forces from the experience the last drop, sweet or bitter, it can possibly give."
I politely disagree. One writes based on one's own experience, but a good or great writer won't limit themselves to their own experiences only. If you see things from only your point of view as a writer, well...
The folks at Creative Screenwriting rightly added this quote right after, to serve as a counter-point-
"The good writer seems to be writing about himself, but has his eye always on that thread of the Universe which runs through himself and all things."