Have you ever tied a fly you were completely satisfied with?
I know I haven't. There is allways a hackle fiber out of place or a miniscule uneveness in the dubbing or whatever that will never be noticed by anyone when the fly is in use. It's particularly a problem with swap flies. I have to force myself not to tie five or six dozen to get one set that won't be any better or worse than twelve of the first thirteen or fourteen flies.
I can think of few acts more selfish than refusing a vaccination.