* ActorInspiredElement: Creator/EmmaWatson and Creator/EzraMiller both worked with the choreographer to come up with some ideas for the homecoming dance.
* ActorSharedBackground: Creator/TomSavini, who plays the woodshop teacher, is not only a Vietnam veteran, he's also a native of Pittsburgh.
* CaliforniaDoubling: Averted. Most of the locations for the movie, right down to the theater where they see ''[[Film/TheRockyHorrorPictureShow Rocky Horror]]'', are filmed in their original locations in UsefulNotes/{{Pittsburgh}}.
* CreatorBacklash: Minor example. Emma Watson says she refuses to watch her kissing scenes or the ''Rocky Horror'' scene.
* DawsonCasting: Averted with Ezra Miller as Patrick, who was 18, but played straight with 21-year-old Emma Watson as a high school senior. Logan Lerman was 19, three years older than his character.
* EnforcedMethodActing: The young actors all lived in the same hotel during filming in order to develop believable chemistry.
* FakeAmerican: Brit Creator/EmmaWatson as Sam, Bulgarian/Canadian Creator/NinaDobrev as Candace, and New Zealander Creator/MelanieLynskey as Aunt Helen.
* IWantYouToMeetAnOldFriendOfMine: A minor case. Creator/MaeWhitman and Creator/JohnnySimmons both appeared in ''Film/ScottPilgrimVsTheWorld''. Though they didn't share any scenes.
* PlayingAgainstType:
** Melanie Lynskey is generally known for playing quirky characters. In ''The Perks of Being a Wallflower'' she played the main character's aunt, [[spoiler:a child molester who abused the protagonist and later died in a car crash]].
** Creator/PaulRudd plays a straighter role than usual, as the CoolTeacher.
* PlayingWithCharacterType: Emma Watson playing a clever, plucky GirlNextDoor. But Sam is more of a ManicPixieDreamGirl than Hermione and has some dark aspects to her past.
* QueerCharacterQueerActor: Ezra Miller plays Patrick, who's gay. In real life, they are genderqueer and pansexual.
* RealLifeWritesTheHairstyle: Creator/EmmaWatson having short hair is because she got a pixie cut after wrapping ''Film/HarryPotterAndTheDeathlyHallows''.
* RealitySubtext: Stephen Chbosky is a Pittsburgh native and he watched ''Film/TheRockyHorrorPictureShow'' in the same theatre they filmed those scenes in.
* StuntCasting: Creator/EmmaWatson had just come from the final film in the ''Harry Potter'' franchise, a global phenomeon, when this movie came out.
* ThrowItIn: When Sam is reading a card from Charlie, Emma Watson is really reading a personal letter from the director.
* UnderageCasting: A strange example with Miller (Patrick). They were the same age as their character, but they're younger than Lerman (Charlie), while their character is a few years older and acts as a sort of big sibling mentor figure to the wide-eyed Charlie.
* WordOfGod: Stephen Chbosky denies that Candace's abortion subplot was cut to avoid an R-rating. According to him the scene occurred right after Charlie's break-up with Mary Elizabeth - and it was cut so as not to affect the pace of Charlie being ostracised by his friends. The film was rated R anyway and only changed to PG-13 after an appeal.
* WhatCouldHaveBeen:
** Creator/JohnHughes originally had the film rights and planned to make the movie more as a dark comedy. Creator/ShiaLaBeouf would have played Charlie, Creator/KirstenDunst as Sam and Creator/PatrickFugit as Patrick. However his sudden death meant that the project was shelved, and eventually made as an independent film with the original author directing.
** A scene with Candace revealing she's pregnant and Charlie helping her get an abortion was cut from the film. It explains why Charlie and Candace's relationship improves afterwards.
** Alice being a lesbian was cut from the original book. Likewise with Sam and Patrick being chain smokers (because in the 90s EverybodySmokes) and Charlie's smoking phase was dropped.
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