I came up with the idea of a wizard family hiring a maid who was seriously bad at her job. Always breaking things and having an overall poor attitude toward her employers. So one day the head of the household curses her with a tail that would grow one foot each time she did something that went against her job description, be it not doing a thorough cleaning job or simply neglecting to address members of the family with respect.

Not long after being cursed, she's already built up quite the annoying appendage. In fact, it's making her even clumsier and ill-tempered than before.

She was also cursed to have cat ears, but that was more an aesthetic decision on the part of the wizard.