Everybody is there own worst critic. In general, you know the mistakes but nobody else does. And unless you point them out to other people....they don't see it, they see a beautiful quilt. Practice and experience will give you the confidence to not be so hard on yourself. There is always something to learn, different techniques, tips, etc. I am by no means an expert, but I feel more confident than when I first began. You will probably always know where you feel you flubbed up, I think that is normal, just don't fret over it.