They can be blind in ways other than artistic ones. They may have you nailed as to technique and how expressive your vision is or isn't, but may be psychologically ignorant enough to deliver their critique in a way that discourages.
Originally Posted by MurrayMinchin
Since the only bona fides which count with me is a photographer's work, I discount any comments from photographers I don't know or whose work does not impress me. This includes complimentary remarks as well as damning ones.
The best critiques I've received were insightful and instructive enough to show me the error of my ways, often very blunt, but not crossing the line which prompts me to say in anger, "I don't need this abuse. I'm giving this shit up." Michael Smith is a master at this. He's said some pretty rough things about prints I'd showed him in the beginning, but the end result was mastery of my craft. He knows just how far to push the indignation envelope to get maximum motivation out of the protege he's critiquing.