Please adopt and extend:
The All Times Must See Science Fiction list.
Starting off with some very good candidates:
2001: A Space Odyssey
Dark Star (film) (1974)
THX 1138
I don't know either. I'll start of with those, if you don't at least know 2 of them ... please, don't even bother to try to add another one.
But if you do......... you're welcome to expand this All Time Must See Scifi List as you see fit.... (And yes, maybe even expanse fits in there.. but no less)...
Here
you
go: