There's a rare humorous example of an Empty Stepford Smiler in Annie Hall, with a couple that Alvy Singer approaches on the street for relationship advice:
Alvy Singer: Here, you look like a very happy couple, um, are you? Woman: Yeah. Alvy Singer: Yeah? So, so, how do you account for it? Woman: Uh, I'm very shallow and empty and I have no ideas and nothing interesting to say. Man: And I'm exactly the same way. Alvy Singer: I see. Wow. That's very interesting. So you've managed to work out something?
Carolyn Burnham from American Beauty is a prime example of this trope, subscribing to the adage, "In order to be successful, one must project an image of success at all times."
The Marvel Cinematic Universe version of Thor didn't start like this, but falls into it by Avengers: Infinity War and Avengers: Endgame. In Infinity War, he still jokes and smiles like he did in Thor: Ragnarok, but is very much grieving over everyone and everything he's lost up to that point and pursuing vengeance against Thanos because it's the only path left to him at this point, as he admits to Rocket Raccoon. In Endgame, after the Time Skip he becomes a grotesque parody of a jolly fat man, seemingly happy and carefree but actually being wracked by guilt and self-loathing and trying to bury himself in alcohol to compensate. Plus he still has a minor meltdown at the mention of Thanos' name — especially because he did get the vengeance on Thanos he wanted, and it didn't help his issues at all.
Black Rat: Asuka always smiled regardless of the circumstances, to the point that Kanako called it creepy, and Ryota and Skai both tell her to stop. Shortly before her suicide, she confesses to Kengo that she is not always smiling because she is happy.
Violet Beauregard's mom has definite Stepford vibes, especially regarding her perfectionist coaching of her daughter. She's played, surprise surprise, by Missi Pyle, patron saint of this trope.
Willy Wonka is recast as a Stepford Smiler whose zany persona masks a lonely Manchild longing for personal connection and a sense of family.
Cloud Atlas: The fabricant waitresses are genetically engineered to always smile.
Katherine in Cruel Intentions pretends to be an upstanding Junior League-type schoolgirl, when in reality she's an oversexed, scheming coke fiend who takes out her frustrations on her fellow female classmates by persuading them to sleep around and ruin their reputations as a result.
The film version of the book Dangerous Liaisons (from which Cruel Intentions, above, was adapted) has the Contesse de Merteuil (Glenn Close) outright state that she learned to smile even when she didn't mean it.
Contesse de Merteuil: I learned to smile while under the table I was sticking a fork in my hand.
In The Dark Knight Rises, John Blake lost his parents at an early age, and practiced smiling in front of the mirror so that people would think he outgrew his "angry little kid" phase. This is how he knew Bruce Wayne was Batman. He recognized a fellow Stepford Smiler.
In The Death of Stalin, pretty much everyone in Stalin's inner circle. When Joseph Stalin says smile, they smile, when Stalin says laugh, they laugh. After Stalin's eponymous demise, this continues during the Succession Crisis, with the Central Committee playing friendly while planning to manipulate, betray, and sometimes outright murder one another.
The Japanese short film "The Dolls with Attitude" has an extreme example in the main character: after years of forced smiling, her face one day hardens into an unmoving, permanently smiling porcelain doll mask, but no one but her seems to notice and her cheery smile leads to her becoming a popular idol. At first, it just looks like a mask that she can't remove no matter how hard she tries, until she smashes her forced smile to pieces with her microphone during a live performance, revealing that her old face is completely gone and she's completely hollow underneath her current one. In a Bittersweet Ending, she's freed from her permanent smile and rebrands herself with a goth/punk theme.
Paul and Mary Bland of Eating Raoul are probably the world's most upbeat and together conservative couple ever, even as they descend into theft, murder and cannibalism.
Speaking of Tim Burton, Edward Scissorhands features a good number of Stepford Smilers.
Played with in the film Far from Heaven in that the housewife genuinely had a wonderful cliche 1950s suburban life. Then it began to crumble around her....
In First Man, Janet Armstrong is serious and not prone to smiling often, but is forced to put on a wholesome smile for the dozens of reporters who constantly lurk around her house or hang around for promotional photos.
Veronica: If you were happy every day of your life, you wouldn't be a human being, you'd be a game show host.
Played hilariously in Hot Fuzz. While by all accounts, Sandford is a picturesque British village, and all its citizens extreemly happy with their lives, it's revealed that that's all a cover for the fact that most of the town's elderly senior citizens are murdering people – in order to keep the cover. That's right, in order to keep winning the Village of the Year award, the Neighborhood Watch Alliance kills anyone they find unsavory enough to ruin their chances of winning Village of the Year.
In Invasion of the Body Snatchers, being absorbed by the pods turns you Empty. By the end of the movie, this happens to either an entire town or to the entire U.S., depending on whether you're watching the original version or the 1978 remake.
Lucille Slocumb in Kingdom Come maintains the role of cheerful people-pleaser and peacemaker while under the stress of struggling with infertility, her recovering alcoholic husband, Ray Bud, planning her father-in-law's funeral, and dealing with a group of crazy relatives and friends. At one point she goes into a bathroom and downs "nerve pills". She finally snaps at the viewing when she comes across a bucket of chicken that triggers memories of a traumatic experience. The next day Lucille nearly has another breakdown when the funeral is delayed because of the preacher's "intestinal difficulty" and Ray Bud threatens to yank the bathroom door off the hinges, telling Ray Bud, "I don't have my nerve pills on me today!"
Last Night: Patrick's sister Jenny spends most of the movie cheerfully acting like a party is going on rather than The End of the World as We Know It. However, there are some signs that she's not as tranquil as she seems. Most notably, she nervously closes her eyes as the ominous wave of light heads toward her and her friends, although she otherwise remains composed.
Karen from Love Actually is a more positive version of the trope. She tells one of her friends whose wife has recently died that he shouldn't openly cry because "people hate sissies". When she finds out that her husband bought his secretary an expensive necklace for Christmas she only cries in private but puts on a smile when she returns to her kids in the living room.
Mean Girls: Gretchen (the 'one small step from a complete nervous breakdown' version, rather than the 'empty inside' version).
Why should Caesar just get to stomp around like a giant while the rest of us try not to get smushed under his big feet?! What's so great as Caesar, hm? Brutus is just as cute as Caesar, Brutus is just as smart as Caesar, people totally like Brutus just as much as they like Caesar, and when did it become okay for one person to be the boss of everybody, huh?! Because that's not what Rome is about! We should totally just STAB CAESAR!
The "Machine Man" in Metropolis when made to look like Maria, is literally Empty (because she's actually a robot). Somewhat subverted because the main character figures out from her actions and the beliefs she espouses, but no one else does. She even laughs as she's being burned at the stake, before her true form reveals itself.
Tilda Swinton in Michael Clayton makes every effort to appear a confident and poised professional who loves her job, but behind the scenes she's a timid, nervous wreck.
Gina McKee plays a particularly creepy variant of this in Mirrormask.
Black Queen: Because we are...what? Guard: Not a home to Mr. Grumpy, Your Majesty. Black Queen: Exactly!
Victoria and Sally from Oblivion (2013). They veer into Uncanny Valley levels real badly (but for different reasons) by the movie's climax.
John Candy's character Del in Planes, Trains and Automobiles seems to be an indomitably chipper guy until it's revealed in the end that he's a deeply depressed widower.
Most characters in Pleasantville are Stepford Smilers, what with it being a 1950s sitcom world made real. Eventually the teens who got zapped into Pleasantville help break the townspeople out of the trope.
Norman Bates from Psycho. Outwardly smiling and charming, but oh so unwell behind the mask. It's even more unnerving because Norman himself is so unstable that he acknowledges his Stepford mask slipping on and off:
Marion: Sometimes, we deliberately step into those traps.
Norman: I was born into mine. I don't mind it anymore.
Marion: Oh, but you should. You should mind it.
Norman: Oh, I do (laughs) but I say I don't.
Conner Rooney in Road to Perdition smiles when he is feeling shamed or humiliated, particularly when his father shows favoritism to Michael. When Peter asks him why he's always smiling, he leans down and deadpans, "Because it's all so fucking hysterical."
Christie-Masters-Christiansen from Romy and Michele's High School Reunion turns Depressed after her high school glory days are over. She pretends her unfulfilling life and loveless marriage is domestic bliss, and that her unfaithful barfly husband is "in real estate" when really he nails drywall for her father's company. When she finds out her former underlings are happier than she is, she even tries to convince them they should be jealous of her.
Played for Laughs in Shock Treatment: Denton is a hybrid of a TV station and a town, so naturally it encourages its residents to be shallow, cheerful consumers.
In the second half of Shredder Orpheus, Orpheus enters a depression after losing Eurydice, but at first he seems fine as he performs in concerts and skateboards with friends. Later, he admits to Linus that everything feels fake, he doesn't know who he is, and he doesn't have a life without Eurydice.
The Stepford Wives: The wives are a kind of Empty type, being robots. They all have huge plastered smiles on their face and are perpetually in a happy, accomodating mood, all of which belies that they feel nothing below the surface.
The Stepford Wives (2004) had a gay couple, one of whom, played by Roger Bart was a male example. The main 'leader', played by Christopher Walken was one, too. Said male leader was a robot, built and programmed as "the perfect stepford husband" by Glenn Close's character to cope with her husband's adultery, and perhaps even her murder of him.
Lenny in Strange Days maintains his chipper huckster facade in public, but in private he's deeply depressed.
Noriko in Yasujiro Ozu's Tokyo Story is constantly smiling, even when agreeing with his sister-in-law that life is disappointing. She only breaks down once, near the end of the film, when she admits her loneliness and shame brought on by her husband's death.
Meryl is an utterly creepy example of this trope. Almost everything she says is a sugary sweet soundbite that sounds like it could have come direct from a commercial, which gets even creepier when she's nattering on about cocoa when her husband is on the verge of a psychotic breakdown. Of course, since she's actually an actress portraying the main character's wife on a 24/7 television show — and according to theWord of God, is a complete fame whore who gets a payrise every time she shills something successfully — practically everything she says is a commercial of some sort.
Marlon, Truman's best friend, is also this according to Word of God. He actually became Truman's real friend over the course of their lives, and underneath the image of beer-swilling party animal, is a deeply broken over having lied to him. In a deleted scene, he turns a blind eye to Truman's escape.
Laura in Very Bad Things. Absolutely nothing is going to spoil her big day. The Downer Ending brings the suburban dream crashing down around her ears. And results in her being Driven to Madness.
Constance Blackwood in We Have Always Lived In The Castle. Her sweet smiles, lovely '50s outfits, and perfect domestic skills conceal huge amounts of trauma and family dysfunction.
In When a Woman Ascends the Stairs, Keiko, also known as "Mama", is like this - she's a respected hostess with a number of male clients who like her (other hostesses also like her), and she's warm and friendly towards all of them, but underneath, she's melancholy and sad, hating every part of her life.
Chris and Belle in The Woman are a happy, successful, traditional couple with three children in the suburbs... who keep a feral woman locked in the cellar, ostensibly in an attempt to "civilize" her. And even before she came into the picture, there was a heaping helping of Domestic Abuse going on. Belle eventually snaps out of it once she realizes that her husband and her son are raping the feral woman.
Gary King in The World's End, despite projecting a highly hyper appearance, is a depressed man who's aware he's lost any chance at a decent life.
" has an extreme example in the main character: after years of forced smiling, her face one day hardens into an unmoving, permanently smiling porcelain doll mask, but no one but her seems to notice and her cheery smile leads to her becoming a popular idol. At first, it just looks like a mask that she can't remove no matter how hard she tries, until she smashes her forced smile to pieces with her microphone during a live performance, revealing that her old face is completely gone and she's completely hollow underneath her current one. In a Bittersweet Ending, she's freed from her permanent smile and rebrands herself with a goth/punk theme.