Most embarrassing scene to observe as an instructor? Asking a highly experienced captain to switch off his flight director, autopilot and autothrottle and demonstrate his manipulative "skills" at flying a raw data one engine inoperative ILS and go-around. Two go-arounds later due to well outside instrument rating tolerances he requested the use of the autopilot which was given in the end. Later he was asked to pin-point his approximate position in terms of radio aid fixing only and he was unable to do so without much muttering, cursing and saying "Is this really necessary when I have a MAP mode available?"