Positive Reinforcement
Totally agree with Ghengis.
I teach in a University as well as doing a wee bit of flight instruction. I am also a trained assessor in the Corporate world.
Learning theory tells us that Students do better at subjects that they enjoy in any discipline. Communication theory tells us that much verbal feedback is lost to background noise, misinterpretation and short term memory.
Therefore written dox, read in the cold light of day, should, in my opinion, contain more positives than negatives.