Twelfth Night, or What You Will
As a "licensed Fool," Feste is literally licensed to criticize and mock the people around him without getting into trouble. Feste doesn't just bag on people though – he's a pretty wise cat who has a knack for showing others the folly of their ways while making them laugh at the same time. Most of the characters in Twelfth Night appreciate Feste's talents and recognize his genius. Malvolio's the only one who doesn't get it, which is the biggest sign that Malvolio is a complete tool.