There’s a photo, taken in 1936, of Al Jaffee and Wolf Eisenberg, a.k.a. Will Elder, goofing around in the cafeteria of the High School of Music and Art in New York, where they were students.

They’re mugging for the camera, their faces pulled into the kinds of caricatures they would later draw — Jaffee grimacing with his eyes squinched up and nose twisted to one side while shoving a whole sandwich in his mouth, Elder making a cross-eyed Quasimodo face and tipping a milk bottle toward his protruding lips and tongue, their hands clawed and gesticulating — basically acting like wiseass teenagers of any era. But these boys grew up to become two of “the usual gang of idiots” — the stable of artists for Mad magazine, who turned teenage wiseassery into an art form and an institution, and eventually turned all America into one big high school cafeteria.

The announcement last week that Mad would cease monthly publication of new material made me sad in the far-off way you feel when you hear that a celebrity you didn’t know was still alive has died. I was a regular reader of Mad in the 1970s, when the magazine was at the height of its popularity and influence. I learned many things from Mad: who Spiro Agnew was, the plots of R-rated movies like “Coma” and show tunes like “I Got Plenty o’ Nuttin’,’” which the writers of Mad evidently assumed would be familiar enough to 10-year-olds of the ’70s to parody — “I Got Plenty of Muslims,” sung by a black militant. I also learned about black militants.

I also learned from Mad that politicians were corrupt and deceitful, that Hollywood and Madison Avenue pushed insulting junk, that religion was more invested in respectability than compassion, that school was mostly about teaching you to obey arbitrary rules and submit to dingbats and martinets — that it was, in short, all BS. Grown-ups who worried that Mad was a subversive influence, undermining the youth of America’s respect for their elders and faith in our hallowed institutions, were 100 percent correct.