I agree my question called for a subjective answer.To refine it, which film would you take on the proverbial desert island, being allowed only one and you had the means to view it.? Mine would be Casablanca.
Dirty Dancing is a good choice because of the music , it would serve two purposes, but the worst movie to only have to play would probably by Training Day.
I'd cheat and take "Berlin Alexanderplatz" as it's 18 hours long and so help fill any time on my hands! Bit I mean stranded on a desert island and only ONE film.
But if unavailable, "Stalker" - forgot that one, smorodina.