Inspiration for the Work: Palahniuk once had an altercation while camping, and though he returned to work bruised and swollen, his co-workers avoided asking him what had happened on the camping trip. Their reluctance to know what happened in his private life inspired him to write the novel.
Palahniuk has said the book was heavily inspired by a period in his life when he was in the closet, and covered up his homosexuality by acting overly masculine to a self-destructive extent. One specific instance which is almost directly adapted to the book was after he had gotten into a bad fight one night, when he came to work next day with his face bloodied and bruised, Palahniuk noted to his surprise that absolutely nobody commented on his appearance.
Many of Tyler's actions and lines of dialogue are based on things Palahniuk's friends have said and done.
Marla Singer is named after a girl who used to beat up his sister in school and Palahniuk decided it was the most hateful name he could think of.
Acting for Two: According to Pitt (from the DVD Commentary), during the scene where the Narrator is in a hotel watching a Welcome video, Pitt plays one of the staff members on the screen.
All There in the Script: In the press packages released for the movie, which came in the form of an Ikea-esque catalog, the main character is referred to as "Jack", as he is on the back of the DVD, and in the booklet accompanying the DVD, where the Chapter list is referred to as "Jack's Chapters". Also, the original screenplay by Jim Uhls refers to him as Jack. On the other hand, in the closed captions for the film, he is referred to as Rupert. Edward Norton reveals that he refers to the character as Jack on the audio commentary on the DVD and Blu-ray.
Banned in China: Thanks to the Chinese policy that criminals in films are not allowed to win, the Chinese adaptation has Project Mayhem be stopped by the authorities at the last minute and the Narrator sent to a mental hospital to be cured of the Tyler personality. Ironically, this made it more faithful to how the book ended.
However, the Chinese government reversed their decision after getting strong pushback from Chinese citizens who had seen the original ending through bootleg versions, and receiving criticism from international human rights groups.
Billing Displacement: The film is about Pitt starting up a club where men beat each other up, and also sharing a few scenes of dysfunctional romance with Bonham Carter. At least, that's what the ads and DVD cover make it look like, both of them billing Pitt first. Actually, the film's protagonist is Norton's (unnamed) character. Pitt doesn't even show up until about 45 minutes in, and near the end, we learn he's really just a visual manifestation of Norton's fractured psyche, not even a real person.
Box Office Bomb: Budget, $63 million. Box office, $37,030,102 (domestic), $100,853,753 (worldwide). At the time of its release, the film was ravaged by critics for its messages, dark humor, and violence, and was K.O.'ed at the box office. Fox owner Rupert Murdoch never forgave executive Bill Mechanic for greenlighting this film, and was rumored to be one of the reasons why Mechanic was fired from the studio (though the official reason was another bomb that also became a cult classic— Titan A.E.). Thankfully, the film managed to become a huge Cult Classic, being voted as one of the greatest movies of all time in multiple magazine polls, and one of director Fincher's best films.
Creator-Preferred Adaptation: Palahniuk has spoken on several occasions about how he prefers the film over his novel, to the point the book now slightly embarrasses him. He specifically mentioned that he thinks the film's ending is far superior to the novel's. He also commends the film for giving more focus to the narrator's relationship to Marla, and has described the narrator's character arc as him "reaching the point where he can commit to a woman".
DVD Commentary: The film has four commentaries. In one, Palahniuk and screenwriter Jim Uhls discuss how Uhls adapted the novel. The track featuring Pitt, Norton and Fincher together in a room is highly amusing, as the actors frequently gang up on the director for laughs but also respect his craft and the info he wants to share. Bonham Carter is dropped in via solo clips, some of which have priceless anecdotal information. Most notably, the very English HBC had no idea how old American children are in grade school, so the "I haven't been fucked like that since grade school" line meant nothing to her when she delivered it.
Defictionalization: The soap is an exact copy of the one used in the film, very popular. It probably doesn't contain the "special ingredient" that Tyler and the Narrator used, though.
When Tyler asks the narrator he wants to be hit as hard as he could, the narrator winds up and... hits him in the ear. Pitt was told Norton would hit him in the shoulder. "Ow! Motherfucker! Why the ear, man?!" is a legit reaction.
Well not so much enforced as it was lucky method acting: Marla's amazingly blasé delivery of "I haven't been fucked like that since grade school" was the way it was because Bonham Carter is British and didn't know that grade school in America was the equivalent of primary school: she thought that meant Marla was a teenager when she first had sex. When Bonham Carter later learned the truth, she was not happy.
The scene of the Narrator and Tyler whanging golf balls out into the neighborhood was captured because Norton and Pitt did exactly that after having a lot of beer. The actors were aiming at the catering truck.
Executive Veto: The line "I haven't been fucked like that since grade school" was a replacement, after the original line was considered too crass by Fox executives, and the writer got them to agree that ANYTHING else was better and they would not veto the line a second time. The original line? "I want to have your abortion." Incidentally, actress Bonham Carter, who delivered the line, didn't know that "grade school" is the American equivalent of "primary school" and was quite displeased when she found out afterwards.
Fake American: British Bonham Carter as Marla. She points out occasions when her accent slips, such as when she says "Cornelius".
At the time, Helena Bonham Carter was mostly known for playing English Rose-type characters in costume drama. The one exception was in The Wings of the Dove, where she'd played the scheming Manipulative Bitch Kate Croy, and had done a quite explicit (and dispiritingly loveless) sex scene. Here she plays the role that cemented her current archetype, which is dark female nutcases.
Most of Brad Pitt's roles at the time had him playing people on the good side of the law, albeit with some being Jerkasses. Tyler Durden is the Big Bad of the film, and a personification of the Narrator's mental illness and anarchistic desires.
None of the characters appear to use or own mobile phones. The Narrator calls Tyler on a payphone and Tyler says he *69ed him to see who called.
One of Project Mayhem's pranks involves pouring petrol into the tube of a CRT monitor so that it explodes when turned on. Another prank involves using electromagnets to wipe the VHS tapes in a video rental shop.
Tyler points out the "cigarette burns" in the film, splices images into the film, and addresses the audience with such intensity that it causes the physical film to nearly be rocked out of the projector. In modern times, digital projection is the standard.
One aversion: in the source novel, the narrator wrote haikus and faxed them to everyone in his office. The film updates this to him emailing the haikus.
Pitt and Norton mostly ad-libbed the scene in Lou's Bar. Fincher cut together the final version of the scene from thirty-eight separate takes.
When the Narrator punches Tyler in the ear, Pitt's reaction was genuine; Norton actually punched him straight in the ear. The original script had Tyler getting punched in the shoulder, but Fincher changed it at the last minute without informing Pitt about it.
Unbuilt Casting Type: Right before Helena Bonham Carter made the switch to playing dark nutcases all the time (she was previously typecast as English Roses in Merchant & Ivory films) Marla is less 'enjoyably nuts' and more 'tragic trainwreck'. It would be argued that this is where her current archetype began, albeit being slightly more realistic than other depictions.
One of the "blips" of Tyler appearing for a single frame before his introduction proper was going to be in the 20th Century Fox vanity plate, but Fox refused to send the filmmakers the animation file.
Tyler was originally going to recite a workable recipe for home-made explosives (as he does in the novel). But in the interest of public safety, the filmmakers decided to substitute fictional recipes for the real ones.
Peter Jackson was the initial choice to direct, as the producers had been impressed with his work on Heavenly Creatures and The Frighteners. Jackson however, although he loved the novel, was too busy prepping The Lord of the Rings in New Zealand. The second choice was Bryan Singer, who was sent the book, but who never got back to the producers (he later admitted he didn't read the novel when he received it). Next to be offered the job was Danny Boyle, who met with the producers, read the book and loved the material, but who ultimately decided to concentrate on The Beach instead.
Producer Ross Grayson Bell initially wanted Russell Crowe to play Tyler, but he was overruled by fellow producer Art Linson, who felt Pitt was the better choice. Bell has since said that he is glad Linson stepped in, as he can't imagine anyone being as good in the role as Pitt proved to be.
Fincher managed to use the Fox executives' Exact Words against them when they objected to Marla's original line from the novel after she has sex with Tyler ("I want to have your abortion"). Fincher agreed to change it under the proviso that he would only have to change it once, to which Fox agreed. When the line was rewritten as "I haven't been fucked like that since grade school," they asked Fincher to change the now-worse line back to the original one, but he reminded them that the agreement was he a). change the line, not make it less offensive, and b). only had to change it once, meaning he didn't have to change it back.