Sixty-odd years ago I had a course in 'Ethnoscience' (broadly, the anthropology of how people understood the world around them), for which I did a paper analyzing a corpus of Moroccan proverbs. The details of the analysis are forgotten, but the professor liked it well enough to ask me for a copy of it. The proverbial as "conventionalized metaphor" has never been far from consciousness ever since, following me through studies in folksong prosody, a library school exploration of the literatures of Folklore, and periodic dippings into Brewer's Dictionary of Phrase and Fable.
...and I remind you that 'Trustworthy' is Number One in the Boy Scout litany
("trustworthy, loyal, helpful, friendly, courteous, kind...")
"We have a saying in the movement that you can't trust anybody over 30."
(Jack Weinberg, San Francisco Chronicle 15 Nov 1964)