Researchers say that knowing how much money your co-workers earn could make you a lot less happy at work.
Research from the University of Carlos III of Madrid shows that when a worker's earnings are less than that of their peers, they can end up working more hours in an effort to catch up, which leads to a feeling of unhappiness.
"The effect of others' earnings on my happiness is negative, because I compare myself to them and it makes me unhappy to earn less than them," Professor Eduardo Perez Asenjo, the study's author, said.
According to Asenjo, the most likely explanation of the study's results lies in social comparisons and businesses should take the research into consideration when trying to keep their employees happy.
"It might be a relevant criterion to keep in mind, when setting salaries, that an employee is concerned not only with what (he or she) earns, but also with what those around them earn," Asenjo said.
"My personal opinion is that employees' happiness is not really taken into account in work environments," Asenjo added.
The study has been published in the Journal of Population Economics.