Anyone who’s ever worked in retail knows the unspoken animosity between the established sales clerk and the chipper new person. In most cases the frost thaws pretty quickly. After all, you’re standing next to the person for seven or eight hours a day. Alfred (Jimmy Stewart) and Klara (Margaret Sullavan) are Hungarians (?!) working the Christmas rush in this beloved Budapest-set comedy from 1940. But this is one of those Christmas movies you can watch all year, like Die Hard or Carol. It’s the fourth installment in Warwick Public Library’s five-week tribute to German-American director Ernst Lubitsch.