The question as asked in Gloria Dean's Blog is interesting to think about, but I believe this is question misses the true point of making art. Art is not about our own assessments of good and bad, it's about the work's relationship to world and its viewers. It is next to impossible for an artist to judge the true purpose or quality of their own work.
Case in point, several years ago I painted a piece about the Binding of Isaac. It is the moment Isaac hands are bound by his father for his sacrifice. The decision to paint the rope tying around his hands as actual Hebrew words from the Bible was automatic. I went through a period of illness, the painting lay abandoned, then judged by me as not so hot. Some time later I had the painting in a gallery and a woman in a wheelchair came in. She was in an almost reclining position. She had oxygen pumped to her nose, and she seem to only have movement in her arms and head. Her wheelchair was electric and she was determined to get into the gallery by herself. She wasn't going to be bound by her illness. I watched her struggle as she finally made it in, immediately drawn to my painting. I could see something in her body language shift as she looked at it.She told me part of her story: she was an ultra-orthodox Jew who had left her faith. Something out the Hebrew lettering and the image spoke to her about her illness. I don't think I've ever had someone understand my own work on a level so much deeper than my own understanding before. By seeing her reaction I received new meaning for the painting which helped me understand my own illness. Clearly, I had made this work for her and never known it. She said it helped to ease her. Sometimes we must surrender to our bonds to achieve freedom.By judging our own work & keeping locked away, we not only block ourselves but block the Divine. Our paintings and works of art can be portals for the creative flow of healing energy into the world. If we are truly creating, it's not coming from us, but through us. We are the filter through which light can pour. A filter is necessary for otherwise, the light would blind us. This is an awesome gift and responsibility- the responsibility not to judge. Even a piece, which by traditional artistic standards may not be great, may have a greater purpose. We don't and can't know. It's up to use to be humble enough to allow the process to work through us.