If you have ever worked in customer service in the food industry, you know that it’s a thankless job. Especially if you encounter a rude customer who flips out when you ask them the simplest questions. So even if you deal with clients on a regular basis and already know the nooks and crannies of the job, some of them can be so irrational that it’s difficult to know how to react.

The author of this tweet @phantomparades shared her own experience. Three years ago, she was dealing with a customer that had an attitude with how she folded the clothes. The buyer asked her to stop and @phantomparades assumed that “she would fold them herself like she said she would. Instead, she asked ‘are you gonna help me?’”

The author was left feeling confused and reminded the customer that she specifically asked her to stop folding. Then the woman “got super heated and said ‘Oh no. Get me a manager. I am NOT dealing with this attitude.‘” This story only shows that some customers get mad for no real reason and it’s the worker who has to take it all in. Sometimes it’s hard to manage your feelings and remain calm. And even the widely known American smile might not be able to save you in intense situations like these.

In fact, research shows that faking emotional expressions all day long drains your personal resources and can take an emotional and physical toll once you head home. We’re not talking about smiling at the customers because they are genuinely kind and respectful. We’re talking about the ones that make you feel stressed and anxious while talking to them. 

 “When [employees] put on that happy face but don’t really feel it—that’s when we start to have problems,” lead researcher David Wagner, Ph.D. of Singapore Management University, explained to the Huffington Post. They observed 78 bus drivers who worked in the U.S. over the course of two weeks. Drivers answered surveys before and after their shifts and also right before going to sleep. 

Mainly the questions were about the quality of their sleep, their mood during and after work, and whether they had to fake their emotions while dealing with the customers that day. Research showed how emotionally draining it is to wear a fake smile. Those drivers that felt the need to put on a “mask” were more likely to suffer from insomnia than those who didn’t. “Emotional acting was also linked to reports of feeling anxious or distressed, and also increased the likelihood of feeling emotionally exhausted at the end of the day. These people even reported more family conflict at home.”

Now let’s talk about the very common saying “The customer is always right.” This phrase is often attributed to Harry Gordon Selfridge, the founder of Selfridge’s department store in London (though some think it was originated by John Wanamaker or Marshall Field—it was a popular mentality among the business magnates at that time). Businesses often use it to make the customers feel special and ensure them that they will get high-quality service.

However, these days more and more companies are turning away from this point of view. According to Alexander Kjerulf, the author of the Chief Happiness Officer Blog, this belief ironically leads to bad customer service and there are a few reasons why. First, it makes employees feel unappreciated. Companies should trust their workers over unreasonable customers because doing otherwise could cause resentment among employees.

Also, it gives annoying customers an unfair advantage. If a business is using this slogan, “abusive customers can demand just about anything – they’re right by definition, aren’t they? This makes the employees’ job that much harder when trying to rein them in.” This also means that such clients will get better treatment than they actually deserve, and that just seems wrong. 

So if you ever end up in a situation where a customer is being rude to you, try to remain calm and don’t take it personally. It sounds hard but remember—they are probably not angry at you. Maybe they have some issues at home or work that keeps building up and even the smallest inconvenience can throw them off. Take a few minutes to yourself, talk to your co-workers and try not to let the stress linger inside of you after the situation is resolved.