Shut up, writing demon!

This post first appeared on my Red Room profile

If you're anything like me, you'll have your very own "writing demon" - an internal self-defeating little joy-sucker who spends his or her time telling you that nothing you ever do will be any good.

I keep toying with the idea of giving mine a name. He might get named after somebody I know at work who spends all her time creating trouble and causing disharmony, impacting on other people's ability to do their jobs properly, and with confidence. If anybody tries something new - or tries to do something in a different way, and it ends in what is now euphemistically called "A learning experience" (viz. a mistake), she'll curse the person to anybody who'll listen, calling into question their professional competence, the quality of their character, even the level of their intellect. See, my writing demon is exactly like that.
Here's a list of the things my writing demon likes saying (yours probably says similar stuff to you)...

"Who in their right mind is going to want to read that?"

"This story is never going to come right. Might as well give up."

"Why are you bothering with this?"

...and worst of all...

"Nothing you ever write will ever be any good."

On some days, it's a struggle to wrestle him into submission, and to get him to stop with the negativity. He's fond of telling me that I'd be better off in the garden, or in the kitchen, than at my desk. On those days, I just tell him to shut up.
What does your writing demon say, and how do you get him to mind his own business?