A Stanford management expert reports that jerks and slackers can cost a company in productivity.  See ABA Bar Journal report.  Stanford professor, Robert Sutton finds that negative workers, pessimists, jerks, or angry, nasty people bring the rest of the work force down.  Negative people can reduce enthusiasm and change the mood, reports the researcher.  In one experiment, researchers found that just one slacker or jerk can bring down productivity by 30 or 40%.  

A clothing retailer fired a top-producing salesman but found that overall productivity increased after the difficult personality left.  Sales overall actually increased 30% after the bad apple left.