When I was in high school, I had an English teacher who gave me writing critiques that I felt were harsh and unfair. This was in a class where we had to read our writing aloud to the rest of the class. Once I said to this teacher, "Why are you so hard on me? I'm the best writer in this class!" (and so modest, too)
She said, "Yes, you are. And that's why I expect more of you. I'm hard on you because I know you can do so much better if you tried harder."
This was both humbling and inspiring to hear.
And this is one of the reasons I'm hard on fellow bandsters. I may be the best writer (we could argue that point). I'm not the best bandster. I don't pick on other bandsters because I think I'm better than they are, but because I think they could do a lot better if they tried harder. Getting an "A" grade for underachievement will not help anybody achieve their goals. In my opinion.
Let me use another analogy. When I was active in Overeaters Anonymous, I picked a sponsor who had several years of "abstinence" from compulsive overeating and who inspired me. She was unlike me in many ways, but I wanted to live my life with her combination of sober sanity and wild enthusiasm. One of the things she required me to do was call her every morning and commit my day's food plan to her. She didn't care what specific food plan I followed, she just wanted me to commit to following it for one day. The next day, I would tell her if I had lived up to that commitment. It was disconcerting to hear her say things like, "How could you have made a better choice in that situation?" But if all she had said was, "Oh, poor Jean, it's so tough to say no to Twinkies when you're so stressed out," she wouldn't have been teaching me anything I needed to learn.