Most of us have had to endure a corrosive fellow member of staff on one or more occasion during our working lives.
He or she may in fact be good at their job, but their bad behaviour - everything from selfishness, bullying, rudeness, being overly-domineering, or even just being constantly too loud and opinionated - and can have a devastating impact on staff morale.
In academic circles, such a problem employee is now more often described as "toxic".
One 2015 report by Harvard Business School estimated that keeping a toxic worker on the payroll can cost an average firm more than $12,000 a year.
A separate study said that the annual financial impact of a toxic employee could be even more onerous.