Which it is. One of the most quotable movies of all time. If memes were a thing in 1942, it would have been the king. Still quotable today.
(Edit: according to Phil Tippett who did the initial character design for the RotJ Jabba puppet, when he asked Lucas directly "if there was an actor that was going to play Jabba the Hutt, who would it be?" Lucas answered "Sydney Greenstreet". https://www.youtube.com/watch?v=3GXrQ-L-ROs&t=599s )
I don’t about best of all time but it sure is outstanding.
So I did a little searching and found in the nineties it was in the planning stages. The play ran on London's West End for only six short weeks and the Broadway producers abandoned the idea. Maybe the couple did not realize they were not writing a play but a movie script instead?
The Italian and French soldiers walking into the bar, and the Italian not able to get a word in edgewise.
The German couple saying, "Leibchen, what watch is it?" "Six watch" "Such watch" because that is the literal translation into English of the German "uhr".
The singing of "La Marseillaise" by extras who were mostly themselves refugees from Nazi-occupied Europe -- the emotion was real.
I've heard a lot of stories in my time. They went along with the sound of a tinny piano playing in the parlor downstairs. "Mister, I met a man once when I was a kid," it always began. (Rick is calling Ilsa a whore.)
Every scene is a gem.
But, of course, it didn't end up that way.
[1] https://biblioklept.org/2013/05/26/casablanca-or-the-cliches...