The Butcher in Alex Cross is very polite in his phone conversations with Cross, even addressing him as Dr. Cross. He never raises his voice, and he expresses admiration for one of his victims' ability to withstand pain under the torture he inflicted on her.
Jack Nicholson's portrayal of The Joker in the Tim Burton Batman movie qualifies as this, like in his scene with Vicki at the museum and his scene with Bruce and Vicki at Vicki's apartment.
Christopher Walken again in Batman Returns. His Max Shreck is a master at balancing his dual roles of gentleman and thug, acting just menacing enough to be chilling while also being just charming enough to let you know that no one would ever believe you if you ratted on him. Like when he catches Selina Kyle looking over his secret - and illegal - plans to stockpile electrical power:
Max: Who would you say this to? Selina:[nervously] Nobody. Max: What did... curiosity do... to the cat? Selina: I'm no cat. I'm just an assistant. A secretary. Max: And a very good one. Selina:Too good?
In Big Game, Hazar acts very friendly and professional when explaining to a hapless tour guide that he's about to shoot down a passenger plane, that he's going to kill the guide and that the man better start running. He retains the disposition thoughout the film.
In Cabin by the Lake, Stanley is a reclusive but popular member of the community and acts like a good-humored horror fan at the local film club's movie screenings. It's a mask, as he's actually an emotionless psychopath who murders women for his own amusement.
In Chinatown, this is the facade that Noah Cross hides behind. Beneath, Cross is a living example of what a man is capable of doing if he had no moral scruples and no law to stop him.
Cross: See, Mr. Gittes, most people never have to face the fact that, at the right time, and the right place, they're capable of ANYTHING.
Peter Stormare as Lucifer, in what's easily the best scene of Constantine. Lucifer manages to be hilarious and genuinely creepy at the same time.
Creepshow: Richard (played by Leslie Nielsen) from "Something to Tide You Over" puts on a friendly facade as he's extracting his revenge. He talks to Harry almost like he's meeting an old friend he hasn't seen in a while, while arranging to bury him alive and drown him and gloating about how he already murdered his wife.
A pretty blonde Southern woman in C.S.A.: The Confederate States of America (which is based on the premise that the South won the Civil War and slavery has survived into the 21st century) hosts a slave auction on the Internet and delightfully coos over some cute "pickaninnies"—black children being placed on the auction block. Probably intended to be Affably Evil—or, come to think of it, just plain affable—in-universe, but due to Values Dissonance, it's more this trope for us.
In Cube Zero, Jax behaves like a jolly enforcer of the sinister government and maintains a pleasant but scornful demeanor while he murders people and hunts down his human lab rats.
Bane, the villain in The Dark Knight Rises, is terrifyingly brutal and utterly merciless. But he sounds like Patrick Stewart after four martinis and a large dose of Ecstasy, calm, polite, and friendly... even when he's crushing your skull.
Death Proof. While stalking his victims, Stuntman Mike takes the guise of a cheesy but occasionally charming guy to hide being a murderous pervert. After getting run off the road, he tries to give his second batch of would-be victims a cheery salute for surviving, but they're not playing around.
Simon Phoenix from Demolition Man seems like a real fun guy to be around. Too bad he's a psychopath who'd probably maim you twice for shits and giggles. Think The Joker in the body of Ruby Rhod.
Die Hard: Hans Gruber puts on a friendly persona, but it's all an act. While he does get a couch for a pregnant lady giving birth, it's simply so he and his men do not have to deal with her screaming. He later forces the woman up to the rooftop with the other hostages to kill them, all for some money.
Gruber: Mr. Takagi. I could talk about industrialization and men's fashions all day, but I'm afraid work must intrude, and my associate here has some questions for you.
Calvin Candie of Django Unchained. Charming, cheerful, and all-around Southern Gentleman...and his Establishing Character Moment has him gleefully watching a pair of slaves beat each other to death. He's also freaking horrifying when he loses his cool. Comparing Candie from when he is happy to when he isn't illustrates the difference between Affably Evil and Faux Affably Evil; the latter is possibly best exemplified when, after Steven exposes Django and Schultz's scheme he maintains his demeanour in a rather more sinister tone to put them on edge, before flipping into Chewing the Scenery-level anger and threat-making, and then alternating between the two states to scare everyone, during all of which he is never actually rude, and he never fails to use "mister" or "doctor" when addressing his fellow white men. His Evil Gloating after his victory also takes this form, as he offers Schultz dessert and cites Southern courtesy as the reason for his insisting that Schultz shake his hand, but here his courtesy is clearly for the purpose of rubbing Schultz' defeat in his face.
Jason Lee as Azrael in Dogma. "I'll have a...Holy Bartender."
Downfall depicts Adolf Hitler like this. Hitler is initially polite and affectionate to the people in his Fuhrerbunker as well as all the poor souls fighting and dying outside for his doomed philosophy. As the film progresses, and his situation gets progressively worse, the psychotic, petty and cruel mass-murdering monster becomes more apparent, as does the fact that his friendly persona is a calculated ruse designed to seduce his subordinates into joining him in death out of guilt or a tragically misplaced sense of loyalty. It did backfire somewhat as some Moral Guardians did criticize the film for depicting Hitler as "too sympathetic".
Agent Kruger from Elysium can act pretty playful and chatty while stalking and brutally maiming his prey. That and when he interrogates Frey, he tells her to cover the eyes of her daughter, because he doesn't like to commit violence in front the kids.
In Ex Machina, Nathan often affects false sympathy or concern to torment his robots, although he does it to Caleb too on a less frequent basis.
Halloween III: Season of the Witch: Conal Cochran is the owner of a mask company, and seems nice at first, but it turns out he wants to kill millions of children. nHe leaves the hero in a Death Trap to die, telling him "Happy Halloween". When he's defeated, he slowly claps his hands, hinting at being a Graceful Loser, however, it's revealed he left a little present for the main character.
The Goblin King in The Hobbit: An Unexpected Journey, while thoroughly unpleasant and evil, is rather jolly and articulate. Gollum is another example because no matter how cheerful and enthusiastic and adorable he is, he still intends to eat Bilbo.
And of course, Smaug himself in The Hobbit: The Desolation of Smaug, true to his portrayal in the book: eloquent, intelligent, and actually a rather polite conversationalist. Though whatever you do, do notinsult his vanity, because he is downright terrifying when angered.
Eddie Quist, werewolf serial killer of The Howling. "Go on, bright boy. Call it a gift."
Snow's previous interactions with Katniss were those of an extremely ruthless, but ultimately pragmatic man who really was trying to minimize bloodshed for everyone and had some level of respect for her. In The Hunger Games: Mockingjay Part 1, in his video conversation with Katniss, he drops the façade, gloating and mocking her motivations while sneering and grinning, yet remains polite and formal.
Inglourious Basterds has Col. Hans Landa who personifies this trope. "Oooh! That's a Bingo! Is that how you say it? That's a Bingo?"
In his first scene he actively does his best to be the perfect guest to Monsieur LaPadite asking for permission to smoke, sit, ask questions of LaPadite, speak in English and also compliments the flavor of the milk he's given. Hans even shows his viewpoint on the Jews saying he doesn't like the propaganda against them.
"If the Jews were compared to an animal it would be the rat. I, however, don't see it as an insult. (brief pause) Consider the environment of a rat. It is undoubtedly dangerous and unfriendly yet they survive which I find rather inspiring."
In every situation where he showcases his (extremely exaggerated) politeness and cheerful disposition, both he and his counterpart are perfectly aware that Landa is a clear and present danger. Landa is a master interrogator, and his prime technique is to put his victim in a number of the most uncomfortable situations possible, all the while blocking their "escape" by behaving as if his companion is thoroughly enjoying the conversation. He pointedly ignores any non-verbal signs of distress from his victim, while forcing him or her to respond in kind - thus preventing any form of retreat, either polite or defiant. Should the victim try to break off the conversation, it would be the victim who transgressed - and that would sink him/her even deeper. Landa even pushes his method to the limits for his own enjoyment - such as when he laughs hysterically, mocking the explanation of von Hammersmark's broken leg (only to apologize a second later), or pours a round of wine, perfectly amiably and as a gesture of peace... to his handcuffed charges. In the latter case, he doesn't even have to savor the wine - quite the opposite, that would make him a petty villain; the fact he didn't even touch his glass makes the gesture even more disconcerting. Not only does his affable manner lets him drive the knife as deep as he wants - it allows him to utterly confuse his victim and make every new strike a complete surprise. In the end, the only characteristic of his that makes him seem Affably Evil is his very insincere Heel–Face Turn, wherein he is willing to help assassinate Hitler himself (and succeeds, too) in exchange for amnesty and a and American citizenship, including a nice house in New England.. He has a few Even Evil Has Standards qualities, however. While he does slowly put La Padite into a corner and force him to give up the Dreyfuses, he does offer him the opportunity to give them up even though he already knew that La Padite was hiding them, when he could have simply had both families killed instead. It's also implied that he keeps his end of the bargain and leaves the Padites alone after killing the Dreyfuses, and he is genuinely horrified and enraged when Raine callously kills Hermann the radio operator.
Mitch Leary (John Malkovich) in In the Line of Fire, who slyly pretends that Agent Frank Horrigan (Clint Eastwood) is his friend in their phone conversations, but is really sneering at him most of the time.
In the movie version of Into the Woods, The Wolf. It's even lampshaded by Little Red Riding Hood's song later: "Nice is not the same as good!"
A lot of James Bond villains are this. They have an outwardly cheerful, friendly and/or suave personality, yet when things don't go their way, their true colors are revealed—be it Auric Goldfinger having Jill Matherson killed by painting her goldnote "epidermal suffocation" after Bond catches him cheating at cards, Franz Sanchez beating his girlfriend and ruthlessly killing those he thinks have betrayed him and Le Chiffre becoming a desperate wreck and torturing Bond in order to get his money back.
John Wick: Chapter 2: Santino seems amiable at first and even admits to being reluctant to push John back into service. However any politeness is quickly proven to be false and delivered with a smarmy backhandedness after it's revealed that Santino wants John to kill his own sister. After the job's complete he takes a hit out on John jokingly saying: "What kind of man would I be if I didn't avenge my sister's murder?"
Vic Hoskins, the human villain of Jurassic World. He acts as amiable and friendly as possible, but it's very obvious from his interactions with others that it's all just a means to an end. Even the people he works with realize it. Just as a testament to how rotten he is underneath this friendly exterior, he has the gall to fake sympathy after his Benevolent Boss (and several innocent people) suffer death by panicked pterosaurs and then use the incident to his advantage and further his plan to use raptors as war machines.
Predating Vic is Peter Ludlow, the human villain of The Lost World: Jurassic Park. While his deference to Ensemble Darkhorse Roland Tembo and his relatively light-handed treatment of the hired mercenaries in his employ may seem to qualify him for Affably Evil status, the first scene he appears in makes it clear he is a stock Corrupt Corporate Executive who has been plotting for years to usurp his uncle John Hammond. He also unapologetically admits to slandering Dr. Malcolm's reputation in the public eye to discredit his expose of the original Jurassic Park incident. Ludlow's priorities become clear in the final act, when he insists on capturing Rexy and her baby and bringing them back to the mainland which sets in motion the T-Rex rampage through San Diego.
Richie in Killshot. Unlike the more calm and reserved Blackbird, Richie is playful and generally puts on a humorously cheerful front. This is all because he's an utterly perverted sadist with no sense of nobility using killing as fun and game.
In The Last King of Scotland, Ugandan dictator Idi Amin behaves like this after the protagonist impresses him. Over the course of the film he acts friendly to the man because he likes his Scottish ancestry (Amin is a bit of an Anglophobe) and generally seems like a visionary modernizer if also a boisterous fellow. However, his friendliness turns out to be a mask which gradually unravels, as he's slowly revealed to be a paranoid, psychopathic despot. Whatever affection he does show Garrigan is mixed with a godawful amount of emotional manipulation, and Garrigan eventually realizes that he's simply a pet to which Amin has momentarily taken a liking, not a friend. Amin tries to torture him to death when Garrigan betrays him for his atrocities.
Magneto with Xavier. They still play chess games together a good 40 years into their conflict with each other. Hell, if you are on his side, he is rather chatty and friendly to you. If you aren't on his side, he can be downright terrifying and still sound unfailingly polite. When Pyro expresses disappointment that he wasn't the one to kill Professor X, Magneto gives him a rather grandfatherly talking-to... with an unspoken, but very real assurance that the next ill words Pyro speaks of Charles Xavier would be his last.
Viper talks in a polite and seductive tone when discussing her evil plans.
Ichirō Yashida continues to discuss philosophy and talk like a kindly grandfather even as he is literally sucking out the life of Wolverine. He also seems to genuinely want Logan to find peace in death.
X-Men: Apocalypse: En Sabah Nur recruits mutants he considers strong enough to be worthy, names them his "children" with affection, and promises them privileged positions in his new world. The moment they underperform, he brushes them off with a contemptuous "Useless." It's cold enough to break the pedestal that Storm put him on.
Iron Man: Most of the villains Tony Stark faces are deceptively charming.
Iron Man: Iron Monger/Obadiah Stane, especially in the scene where he's talking to Pepper Potts. He's as affable as always, but she doesn't know whether he's just making small talk or interrogating her.
Two in Iron Man 2: This continues with Ivan Vanko. In battle, Vanko lets his rage and vengeance run wild, but in the few brief conversations he has with his nemesis, Tony Stark, he is measured and almost friendly, bantering and taking technical advice from Tony, who he likely sees as a Worthy Opponent. One can't help but chuckle at the casual, almost friendly way he talks as he threatens Tony over the phone.
Ivan: Hey, Tony! How you doin'? Heh heh. I double cycle. Tony: What? Ivan: You told me "double cycle, more power." Good advice. Tony: You sound pretty sprightly for a dead guy. Ivan: You too... Ha ha!
Justin Hammer will act like your best friend when it's clear he can't stand your guts.
In Iron Man 3, Aldritch Killian comes across as a classy guy, but all he cares about is getting back at Tony for standing him up 13 years ago.
Ultron is calm, eloquent and has a quick wit, but wants to wipe out the entire human race for the crime of not being perfect. He lied to his allies, showing that he views everyone as pawns for his master plan. He kidnaps one of the Avengers, casually converses with them and tries to freak them the hell out by ripping off his own head. In the end Ultron chats with Vision before deciding that he can't stand him and attempts one last attack.
Some of the best conversations in The Matrix trilogy are between Neo and Faux Affably Evil Agent Smith, who famously insists on calling Neo "Mr. Anderson" even in the thick of battle. One of the best, from Reloaded:
Smith: Now here I stand because of you, Mr. Anderson; because of you I'm no longer an Agent of the system, because of you I've changed, I'm unplugged, a new man, so to speak; like you, apparently free. Neo: Congratulations. Smith: Thank you.
Imohtep from the first two Mummy films occasionally seems to be a fairly polite, friendly guy. However, he is really a monster to people he needs to drain and/or who get in his way. And he even lied about sparing Rick O'Connell and his friends when they're forced to turn in Evey to him, only for him to order some brainwashed followers to go ahead and kill them.
Freddy Krueger, the main monster of A Nightmare on Elm Street. He's good at making a sardonic joke every now and then, but he's scary, at least partially because of it. This is more apparent in the sequels — in the first film, he doesn't talk much.
Frank from Once Upon a Time in the West is a great example. He is a ruthless and sadistic murderer who behaves in a likeable and reasonable way when he's not angry or killing people.
Esther Coleman or better said, Leena Klammer from Orphan. She is a skilled actress, able to convince others she is a sweet, kind little girl. She's not.
In Paddington, Millicent maintains a soothing maternal tone, even when talking about how she is going to kill and stuff Paddington, who she is conversing with.
Manfred von Karma is edged towards this in the Phoenix Wright: Ace Attorneylive action movie. The murder trial against Edgeworth even starts out with him introducing himself to Phoenix and basically saying "May the best man win". And as anyone who played the game would know, it turns out the entire thing was one long plan to get revenge on Edgeworth.
Prime Cut: Gene Hackman's Big Bad acts friendly and jovial at public events like the country fair, but in private he is vicious and psychopathic.
Jules in Pulp Fiction plays this trope to the hilt in the scene in which he acquires the briefcase. Jules acts chipper and polite toward a bunch of young men who are clearly terrified of him and know that he's there to do horrible things. He starts politely imposing himself, aware that they have to agree to his requests to continue his friendly facade. Even after shooting one of the men, he continues acting polite until he finally breaks into scenery-chewing villainy.
The gang leader from The Purge is this. He is extremely polite when speaking with the Sandins, and never swears. He's even listed in the credits as "Polite Leader". He also wants to kill an innocent man for fun.
Mr. Blonde from Reservoir Dogs happily chats along with the other members of the gang, cracks jokes, never raises his voice once or use many bad words in the same breath as he explains how he executed an unarmed 20-year old girl for touching the alarm of the jewelry store they were robbing, and sings and dances along to a song played while he's cutting someone's ears off for the hell of it. It underlines that he is The Sociopath and doesn't really care about his fellow robbers or any of the stuff he's doing.
Detective Mark Hoffman in the Saw series. His affable demeanor is fooling until you've witnessed his true colors under the Jigsaw persona which will pretty much show that his entire affable side's pretty much an act to lower suspicion.
Se7en: John Doe is extremely polite for a Serial Killer, but this just highlights how creepy he is.
Sheriff Sabin, the third villain of Shark Night seems very nice before being revealed to have been Evil All Along. Even after he's revealed as a bad guy, he acts nice toward Nick, offering to play him his favorite song as he is fed to a tiger shark.
Sholay: Gabbar Singh will often toy with his victims for fun, all the while maintaining a grandiose veneer of affability. For instance, he'll loudly laugh along with the rest of his gang before spontaneously executing a group of them for messing up their mission.
Maxim Horvath from The Sorcerer's Apprentice. He's polite. He's charming. He's impeccably dressed and well-mannered. He's witty, intelligent, clever, well-read, culturally literate, and erudite. And he's perfectly willing to slaughter much of the planet's population as part of his plan.
The main villain of The Spirit, the Octopus, has shades of this. He talks to the hero like an old friend, even while having him tied up and detailing his plans to torture him. His reactions to his own bizarre Mad Science is pretty mundane, too.
"Now that is just plain damn weird. Don't you think that's just plain damn weird?"
Nero from Star Trek has his share of killer lines, despite, for the most part, being a humourless Omnicidal Maniac. For example, his response after giving Starfleet a whooping:
Pike: This is Captain Christopher Pike of the Federation Starship Enterprise. Nero: Hi, Christopher. I'm Nero.
Tarkin: Charming to the last. You don't know how hard I found it, signing the order to terminate your life.
Tarkin's rival, Orson Krennic, is no slouch at this either. He puts on a show of politeness and has a surprisingly non-terrible sense of humour, but as soon as anything goes against him, his anger comes to the forefront and he starts having people killed brutally.
Krennic: We were this close to providing peace and security for the galaxy. Galen Erso: You're confusing peace with terror. Krennic: Well, you have to start somewhere.
Count Dooku, at least in Attack of the Clones; he's clearly more respectful towards the Jedi than they are towards him.
Dooku: It's a great pity that our paths have never crossed before, Obi-Wan. Qui-Gon always spoke very highly of you. I wish he were still alive; I could use his help right now.
Obi-Wan: (With quiet fury) Qui-Gon Jinn would never join you.
He shows it by slyly delivering the right amount of hints to Obi-Wan in order to plant the seed of division among the Jedi while painting himself as the good guy. Notice how his behavior in the scene he shares with Obi-Wan is very different to the way he behaves in any other moment of the movie or Revenge of the Sith. (Indeed, in the Sith novelization an extended section taken from his point of view has him musing, though not in such terms, that he's a sociopath.)
M. Bison in the live action Street Fighterfilm. Raul Julia is just grand; the way he talks about World Domination makes it clear that he thinks it's the most natural thing in the world. He also wonders, in apparent seriousness, why people think he's a villain; he has a chandelier of human bones.
In Taken 2 the Big Bad Murad has a trope-defining conversation with Lenora, where he politely tells her that he knows she is completely innocent in his grudge against her husband and that he admires her bravery, for which he is going to send her home...in pieces.
The Shredder from Teenage Mutant Ninja Turtles (2014). He talks to Splinter and the turtles like old acquaintances he's happy to see again, though it's very clear he'd all the more delighted to kill them once he doesn't need them anymore.
Virtuosity's Sid 6.7 is a better Joker than most portrayals of the Joker (and has a natty purple suit to match). At one point, he decides to make music from the assorted screams of his terrified hostages. Loves his work.
Pablo Chacon from We're the Millers, who tends to banter with the Millers at gunpoint, as if he might actually spare them, only to reveal he plans on killing them no matter what.
In most of the Wishmaster movies, the Djinn puts up a pleasant veneer towards his victims while preparing their agonizing deaths. He tends to drop the façade when he switches back into his true demonic form because then there's just no point in even pretending, especially towards the end, when he loses his patience with victory so close in his grasp.
Despite his massive ego, God king Xerxes of 300 fancies himself as "kind". To this end, he tries to be genuinely Affably Evil. Xerxes even congratulates king Leonidas for his efforts and offers to let him keep his rule over Greece as long as he works for him. However, his act starts to slip when he has half his generals executed for a minor failure. Xerxxes act is broken for good after his Villainous Breakdown when Leonidas manages to make him bleed.
TRON: Legacy: CLU is completely affable and polite with Sam from the beginning, and his personal moments of violence always appear to be casual afterthoughts, as in when he is blowing up the End of Line Club, or yelling and slamming his hands into the table at Kevin Flynn's home, making something of a mess, or de-rezzing Jarvis after a last-straw moment of incompetence after a long string of mild-to-major failures. The rest of the time, he is cool, calm and collected, and polite. After all, his most oddly polite line to Sam is "So, you like bikes." complete with a pleasant smile.