I read with interest a piece about a new kit that was being handed around to schools in Queensland, and how to work with the children inclassroom - some of the points the kits made was that teachers should stop using "aggressive" red pens; as red is considered too confrontational, and teachers should leave wrong answers blank, as marking it wrong would have hurt the child's confidence. (more about this kit, and self esteem in education is here).
There's something flawed about wrapping kids in cotton wool, and making life rosey, and painless. I learned more from the comments on essay's which needed work; than that ones which were marked highly. We can't equip students to succeed if we don't allow them to fail.