There's always one... well, actually, in the case of people guaranteed to cause problems in the average office, there are five types, according to a psychiatrist.
They are the narcissist, the anger addict, the passive-aggressive, the guilt-tripper and the gossip, said Dr Judith Orloff.
She defines the narcissist as having an inflated sense of self-importance and entitlement, craving attention and endless praise.
"Some are obnoxious egomaniacs, others can be charming," she said. "Both know how to belittle you and make you serve them - avoid the trap of always trying to please one."
Dr Orloff, a professor of psychiatry at the University of California, Los Angeles, said anger addicts inflict "emotional damage by wearing down your self-esteem".