In season 3 of Stranger Things, Robin names The Apartment as one of her favorite movies. She reveals this while interviewing with Steve for jobs at Family Video in the season finale.
The Apartment is Billy Wilder’s 1960 romantic comedy-drama, starring Jack Lemmon as insurance clerk C.C. Baxter and Shirley MacLaine as elevator operator Fran Kubelik. Its story combines workplace satire, romance, and loneliness in 1960s New York.
Robin also lists Akira Kurosawa’s The Hidden Fortress and Marcel Carné’s Children of Paradise. These choices contrast with Steve’s more mainstream favorites, including Animal House and Return of the Jedi. The scene uses movie preferences to show Robin’s sharp, sophisticated taste and Steve’s less literary personality.
A common mix-up is assuming Robin names only one favorite film. The Apartment is one of three titles she mentions, but it is the first and the answer specifically associated with this question.