OTOH, who defines crap, especially when spouses, friends and
family universally think Dad's work is wonderful and he should sell some
of it?

Arch, I honestly believe that only the person doing the work can
really define if it's crap or not. Family & friends are not only
biased, they are not nearly well enough informed. As turners, we have
all looked at and evaluated far more material (books, videos, shows,
etc.) because of our interest than they have. I've done pieces that
family, friends and others raved about that I was disappointed in.
Once I pointed out exactly what bothered me about the piece and how it
should be improved I most often got one of two comments. Either "I
see what you mean" (usually followed by "but I still like it" or
"You're just too critical of yourself".

While I am critical of my work I don't think I'm overly so. I simply
try to be honest. I've done a number of pieces that I love (a couple
that I even think are perfect) and some that I think are coyote ugly.
The vast majority of what I do fall somewhere in between. In the
final analysis, the only thing that matters is if the piece measures
up to your own expectations or falls short, or perhaps how short it
falls. I honestly believe we do this primarily for satisfaction.
Crap doesn't satisfy.