And here is my (non) advice for the best way not to feel guilty for not finishing: don't start!

But one year, when I won't be so busy, I'll use NaNoWriMo to write one of my stories.

You, not busy?

It will happen, some day. Perhaps when I am rich so I can afford staff to take care of the house and yard, and so I can only work when I want to, on what I want to...

You will still be running around in circles. Just with jewel-encrusted gardening trowels and antique steam-powered industrial sewing machines.

Whooo!