Fault finders are people who identify and point out mistakes or errors. They can come in many forms, such as critics, nags, naggers, umpires, and fusspots. Critics are people who express their opinions about something, usually in a negative way. Naggers are people who constantly complain or criticize. Umpires are people who make decisions in a dispute or game. Fusspots are people who are overly concerned with details or perfection. All of these terms refer to people who are fault finders in some way.