I think if you are prepared to show your work you should be prepared to accept the constructive/helpful criticism that it may receive. It is in this way that we improve our work and the status of the craft. It is only when the way the criticism is presented is rude or nasty that it is not serving any purpose and should be ignored. Someone telling you that your piece is out by 180 degrees is a statement of fact, not hurtful criticism, and can be acted upon to rectify the problem. As someone else has stated, if the binding on a quilt needs more work, I would want it pointed out to me so that I could make a better quilt.