I have lots of no's. Most of my friends would describe me as a boundaried person, and that's been helpful in my life. Helpful in managing my time, in avoiding relationships that are harmful, helpful when I need to defend my values or make hard decisions.
But the invitation to me as I get older is, "RELAX! Relax into the okay-ness of life. Have more fun. Don't take yourself so seriously. See that there are many right ways to do things, many good paths to many good destinations. Don't find security in a 'no' when the universe is giving you a banquet of 'yes.'"
And the Sufi poets (Rumi, Hafiz) have helped me with this. Saved me, really. Here's something from Hafiz, translated by Daniel Ladinsky. Say yes to yes!
I rarely let the word "No" escape
From my mouth.
Because it is so plain to my soul
That God has shouted "Yes! Yes! Yes!"
To every luminous movement in existence.