The Shop Around the Corner (1940)

An exquisite romantic comedy from one of the great German-American masters, The Shop Around the Corner tells a generous story of a group of employees and their boss at a store in Budapest. Two of them - recent hire Klara Novak (Margaret Sullavan) and star employee Alfred Kralik (James Stewart) - are unknowingly falling in love as penpals but in real life, they despise each other. Eventually the pair ready themselves to meet their anonymous correspondent, and with a finale taking place on Christmas Eve, this is a heartwarming seasonal treasure that glistens in black and white. 

More recently adapted for the modern era as You've Got Mail (Nora Ephron, 1998), this original film version is gentle, intimate, and as with all best Lubitsch films, very funny.