Much attention has been given to bullies and manipulators in the workplace, but there are two other types that deserve some time under the magnifying glass.
Fear-mongers take an already contagious item and ensure that it quickly spreads throughout their work units. If they have ties to kindred spirits in other departments, their message of woe can extend to the entire organization within hours. Their theme usually has enough plausibility to gain attention and the impact of their work should not be underestimated. Fear-mongers frequently regard themselves as bold dissenters or tellers of truth. They fail to see the damage caused by their actions.
Stress-producers joke that they don't get ulcers, they give them, haw haw. Unlike the fear-monger, the stress-producers don't pass along bad news, they create it. Unlike the bully, they refrain from overtly cruel behavior. Their technique is to walk into an operation, within minutes have it in turmoil, and then stroll out. Their own mood may rapidly brighten but the victims of their outbursts seldom bounce back that quickly. I've seen stress-producers who are dumbfounded to learn that their explosions are taken seriously. If left unchecked, stress-producers drive off good employees and demoralize those who remain.
In far too many workplaces, these types are permitted to continue their weird ways because their infractions are thought of as personality quirks that are not seriously harmful. That reaction is almost always a mistake. Fear-mongers and stress-producers are corrosive influences that can destroy effectiveness and morale. They should be confronted and corrected.