Yup, me too! I'm like that about everything in life and am consciously trying to improve. I have a really hard time accepting compliments so I tend to knock myself down about everything (quilting, my work...) and I'm really working on changing that.
After I began quilting I started really analyzing the quilts I own that were made by both of my grandmothers. I found all sorts of minor flaws that I had never ever noticed even though I've owned (and used!) some of these quilts for over 30 years. It was actually very cool to find little problems and I even found evidence of a couple spots that had been re-sewn....it made me feel much more relaxed about my sewing!! It made me realize that minor errors are completely invisible to most people, and if anybody DOES notice them that means they're probably a quilter too and they'll understand!