H500, I have thought of something positive to say, reading my own posts I come across as a "Holier than thou prat"
However, I too have done something similar to what you done. Several times. I have also found at times, myself being frustrated at the students lack of progress and let this bleed from me across the cockpit or from the FFS seat. I have sometimes rushed my briefs or briefed poorly.
I used to be a very good pilot and did not make any mistakes but as I get older I seem to have started to make mistakes. Could it just be my age or is it that my greater knowledge, experience and wisdom actually allows me see mistakes now that I was always making. I am not sure! However the process has given me much more empathy with those pilots who I am hugely privelidged to be able to train and check. It's not always the case but I would say that at least I am generally honest after the event. I try to look inward and see how my behaviour can really affect those in my care. Sometimes I am brilliant and the student hangs on my every word and makes tremendous progress. Sometimes the reverse. Sometimes my lack of affection for the poor guy in my charge dulls my enthusiasm. These are my failings not his.
Training and checking is a dynamic fluid process where literally anything can happen. However, I have learned slowly that the whole damn thing hangs on the quality of the brief. I have tried wherever possible to standardise briefs with PowerPoint etc to eradicate the fluctuations in my own performance.
Human factors affect everything we do. We are after all only human.
I recommend to you in great humility to read again some of the CAA guidance for training and checking. You cannot dip your toe in. You've got to swallow the whole thing and try hard to implement i and in my experience it works more often than not.
I have also been very lucky to have myself received always entirely excellent training from vey gifted instructors. I try my best to emulate the best parts of them. They know who they are and like most professional pilots I owe them for everything I have achieved even if at times my own performance sucks.
Look at ourselves first before we critique the student. Ask not why he his doing that but why I have let him get to that point Was it the brief. Was it my demo. Am I Rushing him too far too fast. Easy words to write but not easy to do in practise.
That's all I have. I truly hope you find something useful in this post.
DB