Why Write? and Why Write Memoir?

This originated as a closing letter to students in my last round of Mindful Memoir on Shambhala Online. I realized it would be a good "manifesto" and give folks a better sense of my view of the path of writing. So here you are!

Often, people ask me if their writing is good.
"Is it worth it?"
"Do you think I should keep writing?"
"Is it publishable?"

I am afraid I am never able to give the answer I suspect people want to hear:
Yes.

Why?