And the Bushel Goes Bad

One Bad Apple by Lori Howard.

Never underestimate the impact of one person on an entire team. One person with a problem attitude or divisive nature can stifle communications, make people tense, and ruin the productivity of everyone around him.

I've worked on a couple teams where there was one person like this. In both circumstances I talked to the manager in charge and while both of them were aware of the problem, they were both reluctant to do anything. In one case the problem was so dire, two valuable team members gave notice and left, since they could see no one would do what needed to be done, i.e. fire her. After about 6 months, management finally fired the Bad Apple, but not without significant damage having already been done -- bungled projects, missed dealines, low morale, a toxic environment. They scrambled to try to rehire the two employees who had left because of that one bad egg, but they were already happy at their new jobs and wouldn't return.