Striving for perfection is one thing. Being dissapointed when you
don't attain it is quite another. But how do you curb your own
excessive fussiness?

It's entirely likely that most people will not notice the imperfections
that you may see. They'll just appreciate the quality work.

I don't do woodworking all that much, but I have taken on some
significant projects, including building a 20-string acoustic guitar,
from scratch.

I could show you a dozen places on that thing that just make me cringe.
But most people, to be honest, are just blown away by what they see.
And in retrospect now, I marvel at the fact that I actually finished
it.

From another perspective, don't the teeny imperfections add the
'assurance' that what you're looking at was done with human hands? as
opposed to the cold perfection of manufacture?

As a friend of mine once said - "Art is never completed; it is
abandoned."