La Nana (2009)

Raquel has been the live-in housekeeper for a kind, reasonably wealthy family for half her life, and the joyless repetition of the job has begun to take its toll. Increasingly dependent on painkillers, Raquel resorts to pranks and childish avoidance to antagonize the familys college-age daughter and a procession of new servants, all in the hopes of protecting her precarious power within the home. Her antics successfully push everyone away, until new maid Lucy actually pushes back.