My most memorable QFI was a Welsh Master pilot on the staff of CFS in the mid 60's. If you did not give an exercise back word for word as he gave it then he would reduce you to a gibbering wreck. His recovery to base technique was to do what he called "Free Let Downs". descending to cloud break without bothering Air Traffic because he always knew exactly where he was. 2knots slow on the approach and the screaming started again. Did wonders for the confidence for this ex Valiant co-pilot!!!. Thank goodness for Chas Maynard, totally the other end of the scale.