Good news for those who work for jerks: There's one type of manager who stresses out people even more.  

Employees prefer "consistent jerks" to those who are just sometimes jerky, according to a study from researchers at Michigan State University published in the Academy of Management Journal. That's because constant unfair treatment is easier to stomach than occasional unfair treatment leavened by spates of fairness, the study found. 

"If your boss is always a jerk, you're going to [think]: 'That's just the boss being the boss,'" says lead researcher Fadel Matta. "Whereas if your boss ranges on the spectrum--sometimes they're nice, sometimes they're not--you might say, 'OK what did I do today?' You might have more of an internal attribution about the event."

First, researchers split 160 colleges students into teams of two to complete a stock-picking exercise. They were told that their partner would send them feedback during the exercise--in reality, they were fed unfair ("it sucks to work with an unmotivated person") and fair ("thanks for your efforts during the last round") statements from researchers.  A third of students received only unfair comments, a third received only fair ones, and a third received a mix. The students that received fair and unfair feedback had the highest average heart rate during the exercise.

In the second experiment, researchers asked 95 employees once a day, for 15 days, how they felt they were treated at work that day, and how they felt about their job. The employees who reported receiving fair treatment one day and unfair treatment the next were on average, more dissatisfied with their job and more stressed.

Matta tells Inc. that the best way for managers to prevent their office from becoming unstable is to give employees as much notice as possible about changing work conditions or expectations.

"The best situation is that supervisors always treat subordinates fairly, but we know that's not always possible," Matta says. "Sometimes supervisors don't have the resources or the discretion necessary to ensure that they can mitigate uncertainty."