These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Fan Dumb: If you dare to say you dislike this movie then there are several fans who will label you an idiot who can't enjoy a movie unless it has fart jokes and an explosion every five minutes, or at the very least tell you that you "Just didn't get it".
Freud Was Right: Long phallic space-ships, docking bays opening up to receive them, music climaxing as the ship touches down, narrow slit windows with red light shining through, women emerging from doorways that look like vaginas, the Star Child. Really, this list could go on forever.
Older Than They Think: Most people who watch the film and do not know its age believe it to have come in the wake of Star Wars or thereabout - i.e., the late 1970s. Part of this is the impeccably accurate portrayal of modern spaceflight, technology, et all, and part because of the gorgeous quality of the cinematography and special effects, which rival Star Wars and make it appear as though it were made in the late 70s.
It's really hilarious to see people's reactions when you tell them that it was released before the lunar landing.
Hell, even the computers look better than most of what came between this and the CGI era, or even the real life computers from The Eighties.
Double-hell, this looks better than anything in CGI.
And the technique used to create the "Beyond the Infinite" sequence — a camera trick known as "slit-scan" — was impressive enough to be reused well into the early CGI era. It was later used for ABC's "This is the place to be" ads of the early 1970s, as well as the Whooshing Credits for Superman: The Movie (which improved on 2001's techniques by using a computer-controlled camera) and a whole bunch of pre-CGI motion graphics work in The Eighties.
Weird Al Effect: As time progresses, it becomes more likely that the first time somebody will see something related to the film will be as a Shout-Out made in another more current work rather than in the movie itself.