Margaret profanely telling off Lucy and quitting her job after Nucky sets her up in a fancy apartment.
Jimmy, Al, and Torrio taking out Sheridan and his men.
I think you'll agree that Greek Town belongs to us now.
Van Alden stopping the entire St. Paddy's Day festivities cold and punching out the guy who mouths off to him: "Would anyone else care to interfere with the court-appointed duties of a federal agent?"
Coupled in the second season when he brings down a restaurant that serves alcohol openly. "This is a raid!"
Richard Harrow sniping the guy who disfigured Pearl from across the street, with pinpoint accuracy in the same spot he shot a rival sniper during the war. And he does it with just one eye. Of course, the pipe organs playing in the background only added to it.
And there's his story of watching that other sniper for three days waiting for him to take his faceplate off, and finally seizing the one chance he got.
Jimmy returning to Atlantic City and waking up Lucky Luciano with a hot cup of coffee.
And then Gillian draws Lucky's own gun on him and reveals she's the one who set him up.
Eddie saving Nucky from an assassin (albeit at the cost of an innocent bystander) then shooting him in the leg as he runs away. Quite badass for a character who was entirely comic relief until then.
The Godfather-esque sequence in the season one finale where the remaining D'Alessio brothers are wiped out, as Nucky expertly ties in their deaths toward support for his preferred mayoral candidate as a press conference.
Chalky choking one of the D'Alessio brothers to death was pretty cold but also badass.
Rothstein's speech about once causing a man to choke to death for his own amusement establishes him as someone you most definitely do not want to get on the wrong side of.
Chalky nailing one of the Klan members who just shot up his warehouse from a good distance away.
Margaret immediately figuring out on her own that she needs to get Nucky's illegal business ledger and money out of his office, and taking them from under the noses of the agents tearing the place up.
The fact that she's dressed and acts like when she first met Nucky show how far she's come since then.
She follows this up by returning the money to Nucky, calmly telling him that he should memorize all his transactions from now on and then tossing the ledger into a fire.
Chalky is put into a cell with a bunch of intimidating guys, and their leader is clearly going to make a move against him soon. Chalky just calmly sits pretending to read a book (as he can't actually read) until the right time when he reveals he has connections with all the other prisoners and the "leader" suddenly finds himself without allies in the beatdown that follows. All while Chalky keeps sitting on the bed, not moving a muscle even when the man lunges at him.
Jimmy effortlessly taking down a pair of assassins, one of whom starts with a gun on him from some distance away, with just his knife.
The Commodore lifting an elephant tusk over his head. Particular kudos as it's clear that it requires some effort, so it actually does look impressive rather than him just being unrealistically superstrong.
Nucky throwing the Commodore's dinner to the floor and declaring that he'll destroy him and all his allies. And then openly telling Jimmy just how little his father cared which showgirl he got to sleep with.
Margaret forcing Eli out of the house with an empty shotgun. Granted, she didn't know it wasn't loaded, but badass nonetheless.
Jimmy and Harrow scalping one of the Commodore's backers after the man hit him with a cane, in macabre reference to his having survived a battle with the Sioux.
Meyer Lansky talking his way out of the Mexican Standoff between him and Luciano against three trigger-happy guys in Jimmy, Harrow, and Horvitz. The only thing that keeps him and Lucky from being riddled full of holes is his We Can Rule Together plan to team up and overthrow Nucky and Rothstein.
After two seasons of being The Ghost and then an Extreme Doormat, seeing Rose Van Alden not only talk back to her husband for getting Lucy pregnant and thinking Rose would be all right with them keeping the baby, but strike him repeatedly was long overdue.
Owen garroting a man through his fingers.
Nucky announces to the Commodore and all his allies that he's willingly stepping down, and they can run the town again...then tells Chalky it's time for the city's black population to strike due to the racial unrest the Commodore himself stirred up.
Rothstein's speech that inspired Nucky's plan also qualifies. It nicely summarizes Rothstein's approach to life and business and points out how Nucky can turn things around if he uses the same strategy for his current conflict with Jimmy.
Iíve made my living, Mr. Thompson, in large part as a gambler. Some days I make 20 bets. Some days I make none. Weeks, sometimes months in fact, when I make no bets at all because there simply is no play. So I wait, plan, marshal my resources and when I finally see an opportunity and there is a bet to make, I bet it all.
Dunn Purnsley, when controlling the strike turns round to see at least fifty guys carrying bats and sticks coming to break it up. Does he run? No, he takes his hands out of his pockets and shouts "Hold the line!". Admittedly it doesn't work out too well but all we see of Dunn is him knocking one of the strike breakers to the ground with a single punch before it cuts away.
Manny Horvitz shrugging off a shotgun blast to the chest, trapping the hitman's arm in the door to counter his next shot, and then punching him through a sheet of glass before splitting his head with a meat cleaver.
Jimmy killing his father with his trusty combat knife, with a spear wound that causes him to collapse seconds later.
And The Commodore, of all people, coming to save Gillian, spear in hand.
Richard and Jimmy's Power Walk into the county office and subsequent engineered "suicide" of Boss Neary.
Esther Randolph's "if it please the court" opening statement over the scenes of Jimmy and Richard killing Neary and Margaret marrying Nucky. Futile, but badass, Madame Assistant U.S. Attorney.
Van Alden walks into a situation involving a tremendously angry Al Capone, and within seconds successfully bluffs him that there's some terrible weapon in his suitcase.
Richard killing Manny Horvitz at his own front door in the opening hours of 1923, having bided his time for a year and a half after Angela's death.
Followed two episodes later by him taking offense at Mickey claiming he did it, and marching him straight into Nucky's office at gunpoint to fully explain why he did it, and why he won't be going after Nucky next.
Gyp Rosetti spending an entire day setting up an ambush for Nucky's shipment to Rothstein, forcing them to turn back without even having to fire a single shot.
Margaret entrapping the hospital's head physician into setting up seminars on pre-natal care, using both the local bishop and his wife.
Bugsy Siegel has been sent out on a heroin delivery, with thousands of dollars of product sewn into the lining of his coat. Masseria's mooks catch him, hold a gun to his head - and are immediately blown away by Meyer Lansky. Lesson? Do not underestimate the little man, and don't mess with his business.
Joe Miller, an Irish mafia thug, picked on Jake Guzik for being fat, smelly, and just stopping by the bar he was in to collect for his boss. When he shows up, battered and bloodied, to turn in the collection to Al, Capone first gives him a drink and then goes to the bar Guzik was beaten up at. He proceeds to lay a No-Holds-Barred Beatdown right onto Miller, outright killing the bastard. Before leaving, Al throws a small handful of bills on Miller's corpse, telling the patrons, who had earlier done nothing as Guzik was getting beaten, to "pay for his funeral."
Leander Whitlock giving Gillian a stern talking-to about how she can't just coast through her running a brothel anymore, just a tiny fraction of what she's had coming.
Gyp Rosetti striding naked through the carnage of a failed hit, looking more beast than man.
Benny Siegel walking into Gyp Rosetti's hotel under the guise of a newsboy and in the process, takes out two of his henchmen and causes Rosetti to shoot one of his own. The Awesomeness is diminished by the fact that he kills the actual newsboy without provocation and the tiny fact that he completely failed to kill Rosetti. Maybe next time, Benny.
Nucky managing to sweet talk Esther Randolph onto his side, after humiliating her so badly in the previous season.
Richard threatening to kill Paul Sagorsky if he didn't let go of Tommy. Richard's Tranquil Fury followed by Paul's Oh Crap! face is just perfect.
After Gillian kills an unfortunate man who resembles Jimmy so she can have him declared dead, Richard, who knows full well what's going on, looks her straight in the eye in front of several others and says "Jimmy deserved better than this."
Nucky/Steve Buscemi's juggling act in "Sunday Best."
Gyp's Rage Against the Heavens scene, on Easter no less. Followed by his talking Masseria out of killing him, just seconds away from the bullet.
Van Alden's rage at his asshole fellow salesmen finally boiling over. It involves an iron to the face.
A scalding hot iron, directly applied to the face. OW.
Richard almost choking Paul Sagorsky to death with one hand, after he insults his daughter. Plus giving him a very close view of his face after Paul called him a circus freak. "Would you pay a dime to see this?"
Even better; Once Richard makes Paul apologise he wordlessly puts his mask back on and walks out with Julia following, stepping over her father without so much as a goodbye. Badass.
Joe Masseria's Offscreen Moment of Awesome, overcoming Owen's hit on him and sending his body back to Nucky. Remember, in real life he was known as "the man who can dodge bullets."
Though nothing's happened, yet: The arrival of Eli and reinforcements from Chicago at the end of "Two Imposters" just screams Let's Get Dangerous and Big Damn Heroes. The capper, however, has to be Nucky asking Eli if he was able to cut a deal with Torrio, only for Eli to respond "With him." Cue Al Capone striding out of the crowd of men, cigar in hand as he sums up the journey getting there and says "We need a bath, some chow, and then you and me sit down and we'll talk about who dies." with said cigar clutched firmly between his teeth. Stephen Graham's one line in that entire episode winds up stealing the entire show as he gloriously munches on both his cigar and all of the scenery he can get ahold of.
If Stephen Graham hadn't "grasped" Al Capone before that scene(in this troper's opinion, he already had), he has now.
Samuel keeping his cool and saving a man's life by operating on him on a kitchen table. He is just a medical student and nowhere close to being qualified to perform a procedure that would normally require a skilled surgeon and a hospital. He even keeps operating when Rosetti shows up outside despite the fact that at any moment there could be a gun battle and he could be shot dead. He is not afraid to correct/contradict Nucky and Chalky when it comes to medical matters. One can clearly see why Chalky is impressed enough by Samuel to introduce him to Nucky as "Master Samuel".
Nucky getting rid of three assassins with a shotgun. Why does he even have bodyguards?
The third season finale "Margate Sands" is full of these:
Richard pulls a One-Man Army and by himself slaughters all of Gyp's men. Not to mention that he manages to kill one who put a gun to Tommy's head as leverage.
Gillian attempting to kill Rosetti. It backfires rather horribly, but even Rosetti was impressed.
Rothstein stealing Lucky and Meyer's heroin and selling it to Masseria to cement an alliance.
Nucky successfully double-crossing Rothstein and Masseria, re-establishing himself as the ultimate power in Atlantic City.
To whit: After Rothstein essentially steals Nucky's new distillery as payment for him leveraging Masseria to withdraw his support for Gyp Rosetti, Nucky then uses his new allies in Washington, namely Esther Randolph and Andrew Mellon, to steal it right back in addition to securing Rothstein's arrest in the process. For Masseria, whose goons were simply going back home to New York, Nucky had Capone and Chalky's men ambush their convoy on the way back, slaughtering all of them to a man as a message to Masseria to never attempt to muscle in on his territory in Atlantic City ever again. In one fell swoop, Nucky Thompson defeated the most powerful crimeboss in the country(Masseria) as well as gained his revenge on the other(Rothstein) for an earlier betrayal.
Capone's and Chalky's aforementioned ambush on Masseria's men. Beginning with Capone firing a Maxim gun while smiling behind a cigar and ending with a line of Chalky's men lead by the man himself from the other side, finishing then off.
Gyp's death. Standing on the beach in a wife-beater, Gyp graces his last three subordinates with a horrible/hilarious impression of Nucky, then starts singing "Barney Google", only to be cut off by a knife to the back. Even better, this knife is held by Tonino, Gyp's hapless Extreme Doormat right-hand man, who had put up with increasing abuse from Gyp all season.
Even better is how Tonino doesn't appear to take any joy in it, doing it solely to save his own neck. Therefore, Gyp's death is, to what would be his great chagrin, nothingpersonal. Brilliant.
Despite the problems it causes, it's immensely satisfying when Dunn Purnsley takes a broken bottle to a racist guy who was forcing him into a demeaning sex act at gunpoint.
"Mr Thompson is part of everything. He is in the sky and sea. He is in the dreams of children at night. He is all that there is, forever."
Frederick Elliot's deposition is attended by a very arrogant young man who quickly has Elliot ranting about the "pup" daring to question him. Then he's revealed to be J. Edgar Hoover.
And the The Reveal that Agent Knox is actually an undercover FBI agent which garners an Oh Crap! moment from Elliot.
Emma Harrow saving her twin brother with a shotgun blast after the man who had hired Richard for a hit almost kills Richard.
After spending the whole night watching his father figure and mentor Rothstein lose in poker and suffer through anti-Semitic slurs from one of the gamblers, Meyer Lansky waits for the guy outside. He gives an entire (untranslated) introduction in Yiddish, introducing himself as Mr. Meyer Lansky, a Jew originally from Russia, and tells the guy he's a fat slob and he and the "god of Abraham" are going to kick the guy's ass. He then proceeds to beat the guy to death.
Even in grief, Al Capone is awesome;
Al Capone: Every fuckin' thing that crawls is gonna pay...
The Reveal that Daughter Maitland is a mole and honeypot for Narcisse immediately took a worn-out, uninteresting subplot and made it retroactively awesome.
Chalky's final battle with Dunn Purnsley. We've been waiting to see it for real since their first meeting, and it doesn't disappoint.
Van Alden goes back to Sigrid and shows who wears the pants at home (before he drops them).
Chalky, with a bullet wound in his shoulder, and from the back seat of a car, kills the two deputies Narcisse hired to kill him. And Daughter provides able support by keeping the car from crashing before she manages to put on the brakes.
Eli's stunningly vicious fight with Knox, which actually tops the above-mentioned Chalky/Purnsley one.
Nucky's new bodyguard easily killing a machete wielding attacker by breaking his arm and killing him with his own machete. Then taking the man's ear as a trophy and striding away as the police arrive.
"Greetings from Havana"
Van Alden managing to talk Capone out of killing him after being exposed as a former federal agent, turning Capone's rage on his accuser Lucky.
Mickey Doyle, he of the Chronic Backstabbing Disorder, deliberately misleading the cops who show up at the club looking for Chalky. Although to be fair, Nucky would have likely killed Mickey if he had betrayed Chalky, and Mickey knew this.