Love is a Crazy Thing (연애 / Yeonae) (2005)

Au-jin’s life is a series of boring days, one after another, until she receives a call from a stranger offering her relief from her crushing monotony. To a woman suffocating in a listless routine, the stranger – whom she knows only by voice – is her only outlet, a personal friend she can pour her heart out to. However, her life takes an unexpected turn when a certain Madam KIM rescues her from her predicament, and she meets a seemingly debonair Min-su along the way.