I remember 2 film debriefs at Brawdy
Uncle Ray, who never needed slo-mo or measuring sticks,
Ray: "speed a tad slow, over pitch, early pickle......70' at 6"
Me: "RSO said.....70' at 6"
Ray: "You don't listen to a word we tell you, do you?"
Or a new QWI (now a VSO) grabbing a very old (Spitfire, Kestrel, etc) QWI's SCT film as a demo.
Every run had at least 3 errors, generating a variety of error estimates. We then discovered he had 4 DHs.