* AbilityOverAppearance: Krista was written to be thirty seven, a bitter chain smoker with a raspy voice. Creator/BlakeLively was only twenty-one and had to lobby hard for the role, but ultimately impressed enough to cast her.
* CaliforniaDoubling: {{Averted}}. Thanks to the 25% tax credit created for filmmaking in the Commonwealth of Massachusetts after the success of ''Film/TheDeparted'' (which had been forced to shoot partially in New York), almost everything you see was filmed on location in Boston. {{Played straight}} for an establishing shot, where a shot of City of Angels Medical Center in Los Angeles is used for some reason to represent Beth Israel Deaconess Medical Center.
* CareerResurrection: The widely lauded movie is credited with completely restoring Creator/BenAffleck's credibility as an actor, as well as showing his good promise as a director. It also proved that ''Film/GoneBabyGone'' wasn't a fluke.
* CastingGag: Slaine plays Gloansy, and the climax takes place at Fenway Park, where Slaine worked in his teenage years at a concession stand. He reportedly called going back to the place to shoot the robbery sequence "surreal".
* {{Corpsing}}: When filming the first robbery, Creator/RebeccaHall had a hard time keeping a straight face. The reason was because Creator/BenAffleck would direct while in full costume - as in the skull mask.
* DirectedByCastMember: Creator/BenAffleck as Doug.
* EnforcedMethodActing: Self-inflicted. Creator/JeremyRenner surrounded himself with actual convicted bank robbers in Charlestown to properly get into character as part of his research.
* ExecutiveMeddling:
** The studio wanted the book's ending [[spoiler: where Doug dies in Claire's arms]]. But test audiences disliked it and preferred the theatrical ending - [[SubvertedTrope so it was left in]]. The other ending was filmed and included as an extra in the Blu-Ray release.
** [[spoiler:Dez's death]] was going to be more violent, but because the scene was being filmed at Fenway Park, Major League Baseball would have to sign off on it. They didn't so it was toned down.
* FakeAmerican: Claire and Fergie are played by British actors (the latter is also a case of FakeIrish).
* FakeIrish: {{Averted}} in some notable cases (e.g. Creator/BenAffleck has Irish ancestry, which is expanded into Doug's character, and Slaine is outspokenly Irish-American and it is seen in his performance as Gloansy), but mostly played straight.
* PlayingAgainstType: Creator/BlakeLively, best known as the glamorous Serena van der Woodsen on ''Series/GossipGirl'' at the time, as a trashy alcoholic.
* ThoseTwoActors: Creator/TitusWelliver and Slaine were in the previous film that Creator/BenAffleck directed, ''Film/GoneBabyGone'', which included Ben's brother Creator/{{Casey|Affleck}}. Welliver and Creator/VictorGarber (Claire's boss) would also appear in Affleck's next film ''Film/{{Argo}}''.
* ThrowItIn: The sequence of a cop turning away as he sees the robbers escaping wasn't in the original script. Ben Affleck added it in after interviewing a bank robber in prison - who said it happened to him.
* WhatCouldHaveBeen:
** Creator/MarkWahlberg was the original choice for James Coughlin, but he was too busy filming ''Film/TheFighter''. It was Creator/CaseyAffleck who recommended Creator/JeremyRenner to his brother. Creator/BenAffleck would later call Renner the EnsembleDarkhorse in the cast.
** [[spoiler: Dez's death scene]] had to be edited down because it was deemed too violent. The initial cut had blood splattering all over the ambulance.
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