Accidental Innuendo: "Pardon me, miss. I was giving myself an oil job." Also, "I hope you don't think I could get that stiff in just five minutes."
Alternative Character Interpretation: Did the tiger suddenly attack Altaira because she felt sexual desire, or had it in fact been sent after the captain to assassinate him, and she simply got in the way?
Genre Turning Point: For the next 12 years, this was the space science fiction film to watch, until the release of 2001: A Space Odyssey. Forbidden Planet reached this standard by having production values, story, and scale greater than any sci-fi film before it. Gene Roddenberry called Forbidden Planet one of his main inspirations behind Star Trek: The Original Series, and the film is responsible for creating and/or popularizing most of the sci-fi tropes that we know and love. Today, however, it is most likely known as that film that looks like Star Trek, has a big, funny robot, and features Leslie Nielsen before he was a comic actor.
Robby's voice actor would later team up with Leslie Nielsen again in a quite different project, as the announcer for Police Squad!.
Monstrous entities being born from a person's desires and emotions? Sounds quite similar to the concept of Stands.
Robby's chugging down the cook's bottle of booze like Bender (albeit only to analyze it).
Dr. Morbius' name gets a few chuckles in the wake of the absurd levels of Memetic Mutation surrounding Morbius. It's Morbin' time indeed.
It Was His Sled: The twist that the monster is an Id monster produced by Dr. Morbius's subconsciousness is pretty well known, given that it tends to come up in any discussion surrounding the movie.
Most Wonderful Sound: The otherworldly, electronically generated tonalities that underscore the film. Sadly for Louis and Bebe Barron, their pioneering sound design was ineligible for an Academy Award due to them working independently and thus not being covered by the Musicians' Union.
Pop-Cultural Osmosis: People are probably more familiar with the UK chain store named after this movie than the actual movie itself.
Retroactive Recognition: Yes, that is, in fact, a young Leslie Nielsen, in his most famous "serious" role (and only his second-ever movie appearance). Nielsen himself, who appreciated comedy much more than science fiction, once commented that what he appreciated most about Forbidden Planet still being remembered was that it captured him at a time in his life when he had a great physique.
Strangled by the Red String: Altaira goes from hating the Captain to deep, unbreakable love for him for no reason whatsoever. Of course, when Captain Adams tells Morbius she's joined herself to him "body and soul," he's probably overstating it to bait a reaction from Morbius — and he certainly gets one.
Values Dissonance: The film has a very 1950s view of gender politics, most notably in Adams blaming Altaira for all his men lusting after her just for standing around in a miniskirt. He almost goes as far as to outright say that it would have served her well if she had been sexually assaulted by Jerry.
The Id monster, the one time it becomes fully visible, remains unforgettable to this day. That it was animated makes the Eldritch Abomination juggernaut not one jot less terrifying.
The backdrops are amazingly well-rendered, and can be fully appreciated when viewed on a 4K TV or a projector.
Walt Disney lent MGM one of his top effects animators, Joshua Meador, to help with the effects. Meador's handling of the various laser beams, energy sparks, and the aforementioned Id Monster has a delicate beauty all its own.
The shots of the Krell machine are an amazing feat of model work that hold up well more than sixty years later.
