Smile like you mean it.

A new study conducted by Michigan State University finds that the emotional labor needed to fake a smile for customers and colleagues at work can actually lead to unethical behavior.

The study was co-authored by Brent Scott, a professor in the Department of Management at the Eli Broad College of Business at MSU.

“They feel inauthentic … when people feel fake, they act in more unethical ways,” Scott said.

The study finds that people who regularly don disingenuous smiles are more prone to behaviors like dragging out work to get overtime pay, concealing errors, passing blame for errors to innocent coworkers, and claiming credit for someone else’s work.

Workers who generally deal with the public on a regular basis were generally included in the study.

“It kind of goes without saying that employees wouldn’t always be in such a state … so they have to do things, or act, in ways to cultivate or achieve that display of happiness,” Scott said.

Scott notes that sometimes customers have to do their best to realize that the people they deal with are simply human.

Customers can play their own role in helping employees manage their emotional labor by “realizing that employees aren’t always going to be in a happy mood, and it’s not necessarily anything that the customer did — it could be external events — and not to attribute a bad mood to something that they perhaps did,” Scott said.