Joan Rivers: A Piece of Work (2010)

Filmed as Joan Rivers turned 75, it shows a legend who still feared an empty calendar. She chases bookings, works on material and frets about the next job, and the film never pretends the hustle is glamorous. It is the best portrait here of comedy as a business: the money, the insecurity and the refusal to slow down. Rivers is ferociously funny on stage and startlingly candid off it, which makes this both a laugh and a gut punch.