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.
Special mention to Schifrin's scoring during the church climax of "The Heir Apparent" with Cinnamon trying (with some previously supplied help from Barney) to open a puzzle box that only the woman she's impersonating - who is absolutely not Anastasia - could have opened; this particular cue gets reused often in later episodes. And yes, she does get it open.
Ear Worm: It goes hand-in-hand with the Crowning Music of Awesome. Everybody knows the Mission Impossible theme song.
If you watch a few episodes, you'll also find the incidental music running through your head.
Ensemble Darkhorse: Landau quickly eclipsed star Steven Hill, even though he was only intended as an occasional guest star.
Fair for Its Day: Barney Collier, a coloured man, was The Smart Guy in a band of geniuses. Also, while Cinnamon's primary task was to provide distractions, everyone treated those distractions as vital, and Cinnamon was clearly a respected team member.
Moment Of Awesome: Many - for instance, in "The Legend" Rollin pulls the rug out from under the villain of the week and his scheme to resurrect the Nazis through a dummy impersonating Martin Bormann by... impersonating Martin Bormann. The Oh Crap expression on the Big Bad's face as everyone else heils "Bormann" is priceless.
In "Death Squad," when Barney and his cellmate are about to be hanged by a corrupt police force for crimes they (certainly Barney) didn't commit, Mr. Collier's refusal of a blindfold drives his formerly nervy colleague to take his punishment like a man and similarly decline. Fortunately this doesn't become a Dying Moment of Awesome for either of them, as the rope has been rigged to break by the IM Force as part of the rescue.
Several instalments, like "The Killer," "The Council" (parts one and two) and "The Mind Of Stefan Miklos," are basically Episodes Of Awesome.
In "Robot," Leonard Nimoy plays (in addition to Paris) Gemini - the double of a deceased premier; usually when he or Martin Landau play multiple characters in an episode with makeup on there's still a touch of Identical Stranger, but Gemini/the premier genuinely doesn't look anything like Paris. The makeup department (specifically Bob Dawn)'s Crowning Moment Of Awesome for the series.
Narm: "Some of that dialogue is terrible, isn't it?" - Mission: Impossible writer-producer William Read Woodfield. Example, from "A Game Of Chess" (which Woodfield and his partner Allan Balter, in fairness, did not write):
Jim: Then we're all set except for the typhoid. Who's got it?
Rollin: I do.
Narm Charm: The series is ridiculous and often centers around problems governments would generally solve in a far more straightforward way (as Martin Landau pointed out, "In reality, there'd be an assassination"). But it's still a lot of fun to watch.
Values Dissonance: Originally, the IMF were a group of people choosing to use their specific talents in spy work purely for the good of their nation. (Starting in 1966, still the era of "Ask not what your country can do for you, but what you can do for your country.") This wouldn't have worked in the 1996 movie, so it made the IMF a deeply covert part of the US intelligence services. Even in the time of Richard Nixon, the idea of American agents covertly manipulating foreign countries as heroes was going out of fashion, and in later seasons the IMF spent most of their time working their wiles on organised crime at home. (Although in the revival and the movies they got to travel around the world again.)
Anti-Climax: The Reveal of Brandt's big secret in the fourth movie. The reason behind his secretive attitude? He failed a protection mission that lead to the Disney Death of Ethan's wife. Given how common it is for someone to be a Double Agent or The Mole, its unusual for someone to simply be The Atoner for something they don't actually need to atone for. Saying that, it makes him a unique entity in being a guy capable of action hero moves, but without the usual bravery for it, who is also far more emotional to be so damaged by something Ethan would have shrugged off after a while.
Better on DVD: When it was released in theaters, many people regarded the first film as being extremely difficult to follow, albeit with a great final act making up for things, which in no small part was responsible for the Actionized Sequel nature of the second film. With the benefit of home video releases however, a lot of people have come to appreciate the more nuanced plot of the first film.
Complete Monster: The actions of Owen Davian in the third film (selling weapons to terrorists, killing agents by bombs implanted in their heads, brutally beating up the defenseless hero in front of his equally defenseless wife) are bad enough, but what really sets him apart are his complete lack of any redeeming qualities and incapability of showing any other emotion than annoyance, anger, and a creepy combination of Dull Surprise and sadistic glee . Hearing him count to ten while holding Ethan's wife hostage execution-style is pants-shitting scary.
"What I did to your friend was....fun. It was fun."
Crowning Music of Awesome: The Mission: Impossible theme. The version in the first film even made it onto top-ten charts around the world.
The movie version is so closely associated with Tom Cruise that it's the background music in the infamous "Happyology" award video that kicked off the Anonymous protests against "Happyology". If you listen closely you'll notice there's no looping, someone is actually strumming the Mission Impossible theme for about fifteen minutes.
Ear Worm: You're now hearing the theme song in your head, and it will be stuck there for quite some time.
Ensemble Darkhorse: Ving Rhames who is the only actor besides Tom Cruise to appear in all of the films.
Simon Pegg is so far the only actor aside from Cruise and Rhames to appear multiple times as a team member.
Even Better Sequel: Ghost Protocol is easily the best-reviewed film of the series, with 93% on Rotten Tomatoes.
Fanon Discontinuity: Fans of the original series like to pretend the films never existed mainly due to Phelps turning out to be a villain.
"Funny Aneurysm" Moment: The trailer for the fourth film shows the bombing of the Kremlin, a major symbol of the Russian government. The trailer was played on the same day as the terrorist attacks in Oslo, Norway.
Genius Bonus: From M:I3: When Brassel is dressing down Ethan and his boss, he refers to Davian supplying 'gas centrifuge technology' (used for uranium enrichment) and clarifies that when he refers to him as The Invisible Man he's referring to the HG Wells version, not the novel about race written by (Ralph) Ellison.
Word of God says William Brandt was put in the fourth movie so that he could become the series' new protagonist if Tom Cruise ever left. In the end, Cruise stayed on for the fourth movie...but around the same time, Jeremy Renner did end up becoming The Bourne Series' new protagonist after Matt Damon dropped out of The Bourne Legacy.
Nightmare Fuel: The effects of the Chimera virus from the second film. It has a twenty-hour incubation period, after which it sets about destroying your red blood cells. The medical pictures of its first victim show an emaciated man with horribly mottled skin and blood coming from his nose and mouth, as if he has internal bleeding everywhere, just underneath his skin. What a way to die.
The Burj Khalifa climbing sequence from Ghost Protocol. Just the notion that the slightest slip-up meant a long fall down for Ethan makes the sequence very uncomfortable to watch, especially for those with a fear of heights. Watching the scene in full IMAX just ups the vertigo factor; the sequence is credited with the huge success Ghost Protocol had in IMAX.
Recycled Script: Both the first and third movie involve Ethan being set up by a mole in IMF who isn't revealed until near the end, and who tries to frame the boss of the organization who spends time as an Anti-Villain trying to hunt down Hunt, with the audience left unclear if its because the boss really thinks Hunt is a traitor or because the boss is the traitor. In both their actions force Ethan to go rogue and steal the MacGuffin that the bad guys are after for them, and in both The Mole is in league with an arms dealer. Each movie sees Hunt's family being dragged into the plot to get at him, sees a fairly traditional IMF plot go off without a hitch only for the team to be ambushed after the fact, and features a reference ot Ethan evading airport security despite IMF putting "a guy at the airport".
Sophomore Slump: While some moviegoers appreciated the easier-to-follow storyline. the second movie is considered inferior despite the flashy action. The third and fourth films got things back on track, and are the best reviewed films in the series.
Theiss Titillation Theory: Maggie Q's dress in the third film's Vatican sequence. To quote Phillip Seymour Hoffman's reaction, "You're wearing a tablecloth!"
Complete with Panty Shot when her character draws out a bomb detonator to fake Davian's death from her leg.