I would say the time my skinny tire (1978) caught a groove on a dirt path and I face planted...or the time I rode my bike to school when it was still too cold, hit a patch of ice, flipped sideways onto the street, and ripped up my pantyhose (1977)--I was riding in a SKIRT? Don't remember that, but I do remember ripped pantyhose and road rash. I would say those times, but those were just accidents.
The most humbling thing that happens these days is getting the back crotch of my bike shorts caught on the nose of my saddle when I'm trying to get back on the bike as the light turns green. Sheesh.