Every medical practice manager has to deal with a certain amount of employee pessimism at times. But one overly pessimistic employee can spread his or her negativity to the entire medical practice team if the manager doesn't intervene. This article suggests practical strategies managers can use to deal effectively with a pessimistic, defeatist, gloomy, or cynical employee. It describes two kinds of pessimism medical practice managers may encounter and offers 25 specific management do's and don'ts for managing a pessimist. This article also offers managers guidance for firing a pessimistic employee, including sample language they can use. It provides 10 self-care strategies for practice managers so they can keep themselves from succumbing to an employee's negativity. It also suggests eight ways that pessimism can hurt the medical practice team and describes five kinds of negative thinking managers may encounter. Finally, this article explores defensive pessimism theory and the surprising benefits for managers of some pessimistic thinking.