Actor-Inspired Element: The chest-thumping McConaughey does in the lunch scene at the beginning is something he does to warm up for scenes in real life. Scorcese asked him about it and then had the idea of having McConaughey do it on the next take without telling DiCaprio's to get his genuine reaction.
Awesome, Dear Boy: Jonah Hill made only $60,000 (the lowest possible SAG-AFTRA rate) on the film; he simply wanted the opportunity to work with Martin Scorsese.
Promoted Fanboy: Which could also make him this, since Hill had established as far back as in 2010 (well before he had even earned his first Oscar nomination) that Goodfellas was his favorite film of all time.
Fake Nationality: The French Jean Dujardin as a Swiss banker. Although considering that Switzerland is a multi-cultural nation with German, French, Austrian and Italian influences, it makes sense for a French man to pass as Swiss.
Star-Making Role: Not that she was entirely obscure beforehand, as she was very known in her native Australia, but Margot Robbie's profile was increased considerably by her appearance in this film, to the point where she was widely considered a serious candidate for the Best Supporting Actress category at the 2014 Oscars (though ultimately wasn't nominated). Nowadays, people are beginning to cite her turn as Harley Quinn from Suicide Squad (2016) as her true rise to stardom, with Wolf essentially serving as her as Brokeback Mountain was to Heath Ledger. Fortunately, she didn't have to go through Dead Artists Are Better like Ledger did.