If we’re counting dark comedy (which I do), it’s probably Parasite or Another Round. Of the more conventional types, it’s likely Monty Python and the Holy Grail or His Girl Friday.
Guess I will have to mention this underrated gem ... Life of Brian. Joking aside, some movies I want to mention are tucker and dale vs evil, death at a funeral 2007, and what we did on our holiday.
If I have to pick one, then the 1955 Ealing comedy The Ladykillers.
I know that the Coen brothers did a remake, and I am a fan of most of theirs, but I have no interest in this remake. The original could not be topped, IMHO.