Little [sometimes old] ladies
The Coens pulled together some actresses who did quirky, even by Coen standards.
Mel Novikoff's secretary had me in stitches. I can't figure out who played that role; she did the job brilliantly. Conversations between her and Mel with Llewyn present took dumb to extremes. They talked past each other, with most of it making no sense. She was a typical "been there - done that" bored New York City gal. Her waddling around that hell-hole of an "office" muttering was hilarious.
And, Lillian Gorfein's serious question about scrotums has not been heard in many films.
E pluribus unum