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".
They are the worst for making us say something we will regret, so always take a deep breath and count to ten before responding to them, she advises.
The passive-aggressive is similar to the anger addict, but expresses anger "with a smile or exaggerated concern".
Meanwhile, the guilt-trippers are "world-class blamers and martyrs' who "manipulate you into doing what they desire".
The office gossip "longs to capture your attention with insider information so you like them", but Dr Orloff, writing in her new book The Ecstasy of Surrender, notes that being on the receiving end is humiliating and says you should confront them when appropriate.
- Daily Mail