My Fair Lady (1964)

Gloriously witty adaptation of the Broadway musical about Professor Henry Higgins (Sir Rex Harrison), who takes a bet from Colonel Hugh Pickering (Wilford Hyde-White) that he can transform unrefined, dirty Cockney flower girl Eliza Doolittle (Audrey Hepburn) into a lady, and fool everyone into thinking she really is one, too. He does, and thus young aristocrat Freddy Eynsford-Hill (Jeremy Brett) falls madly in love with her. But when Higgins takes all of the credit and forgets to acknowledge her efforts, Eliza angrily leaves him for Freddy, and suddenly Higgins realizes he's grown accustomed to her face and can't really live without it.