The Apartment (1960)

Billy Wilder’s sweet, sad The Apartment stars funnyman Jack Lemmon in a performance filled with pathos. His C.C. lets the married higher ups at his company use his apartment for their affairs, which is complicated when he discovers his crush, elevator girl Fran, played charmingly by Shirley MacClaine, is one of the mistresses. The Apartment is poignant and perfect.