I'm the first one to admit my own because in acknowledging it existed, I was able to heal from it. I also find talking about it helps others through difficult times.
My mother is a classic example of mrs fix it. As a child, I longed for her attention and approval which I never got. So, when I sought a mate, I married one just like my mother. It ended badly because all he ever did was exactly as you describe here, pointed out the flaws in my self instead of looking at his own first.
My ex attempted on many occasions to "fix" me. I grew resentful toward him. As he did I. Once I gained confidence in going back and re-examining my own life, I realized it wasn't going to work out ever. The final straw was when we disagreed on the way I cooked potatoes. I stuck a fork in them to see if they were done...
I accept him for the person who he is, but it wasn't an enduring relationship or one that would ever last. We are better off now. He is living his dream in the big city, and I am merry homemaker to my family and husband. Both of us couldn't be happier.
We were both of the example, you can't fix what isn't broken. Neither one of us thought we were broken.