Admire a child's hope. Still hope good things of yourself. Of course, children will break rules- which will give criticism merit- but remember that you screw up as well. Be as a positive role model you can; criticize a child constructively; otherwise, they may lose their ability to hope.
You are on point! Being a good model for the kid is the best example. Ruining hope for progress is such a harsh thing to do. I think that few parents realize the trauma they cause to their own offsprings due to excessive criticism