I learned High Tea etiquette. Went to a themed bridal shower at a tea shop and had a wonderful time. 42-year-old women just don’t get enough opportunities to play dress-up and have tea parties.
I learned how to open the canopy of a FA-18 Hornet with the hand crank fitting.
Due to a question that arose in Does this sort of “science” bug you? and to my memory having most (if not all) of the UFO sightings on record being after supersonic flight was attained (late 40’s) I was startled by the dates given, and the situations described in List of major UFO sightings.
Startling, at a minimum, even if the veracity of Wikipedia is not ironclad.