I thoroughly enjoyed your mini-dissertation on micro-expressions. I think it is worth emphasising that there is a big difference between the gormless expression that gets caught in a snapshot and the intense emotionality displayed in a momentary rictus of self disgust.

We do read these fleeting expressions, even if we pay more attention to the person's words. Then we end up feeling confused by the disparity between the person's explicit declarations, and their ill-concealed reactions to their own words.

I am spared the emotional impact of the video but the varied reactions of hilarity, horror, or bewilderment of exes remind me of an essay, "The President's Speech", by the noted neurologist Oliver Sacks, that I mention from time to time. If you've not familiar with it, here's a copy I scanned (for educational and research purposes)

http://www.poetsroads.demon.co.uk/tps.html