Maintaining a positive attitude at work is often cited as one of the keys to success, but staying upbeat can be hard when a co-worker is moody or negative all the time. Dealing with these moody co-workers can be challenging, but by remaining calm, giving them space and monitoring your own responses to their moods, you can maintain a sunny outlook and maybe even inspire them to snap out of the funk.

Emotional Contagion

Researcher Sigal Barsade, Ph.D., in an article in Psychology Today, points out that both positive and negative emotions can be contagious, especially in the workplace. When working in groups, employees tend to “catch” emotions from each other, and those moods can affect the decisions that they make at the office. Dr. Barsade studied different groups that were attempting to make an important business decision. In each group, she placed an actor who was assigned to express a specific emotion, ranging from happiness and serenity to hostility and depression. Unsurprisingly, the overall group interactions mirrored those emotions. The same thing can happen with your co-workers. If your co-worker is moody and depressed when she arrives at work, you can “catch” that mood and start to feel down yourself.

Fight the Negativity

Understanding the potential effect that a moody co-worker can have on your day is only the first step. You also have to work with this person. Understand that rarely does a co-worker’s bad mood have anything to do with you; it is more likely to be related to his own work, something taking place outside of the office or another frustration. Maintaining the, “It’s not me, it’s you” perspective and remaining calm even when your colleague is being distant or negative can help you get through the day and maintain your own positive outlook.

Pay Attention to the Signs

Sometimes, your co-worker will make it clear that they are in a bad mood and not interested in talking. Watch for body language and clues that say, “Back off.” A closed office door, a back turned to you or earbuds in the ears are all signs that someone isn’t feeling very chatty. Moody people will often send out signals that they aren’t feeling great, and it’s up to you to pay attention to them. Some companies have even invested in actual signals for their employees to use when they aren’t interested in chatting, such as a desk light glows green when you are willing to chat, or red when you don’t want to be bothered. If your colleague consistently has off days, consider working together to come up with an informal signal system that lets you know when to tread lightly.

Offer Some Control

One common reason people are moody at work is that they feel overwhelmed with some aspect of their life. While you want to give your colleague a wide berth, you probably need to get some work done too. If you need to meet with them during the day, offer them some control over your meeting. Say something like, “I know you’re busy, but I’d like to chat with you about these numbers at some point today. What time works for you?” If you’ve already scheduled a meeting, follow up to confirm and ask if the time still works.

Be a Friend

Showing kindness to a moody co-worker can be helpful to them. Offer to treat coffee or lunch for them when you go; invite them to take a walk outside, or grab them a snack from the vending machine. Don’t repeatedly ask what’s wrong, but gently say something like, “You seem a bit out of sorts today. Is there any way I can help?” Doing so not only tells your colleague that their mood has been noticed, it gives them an opportunity to either share what’s wrong or adjust her attitude.

When the Problem Continues

Everyone has bad days, but you need to take action if your colleague's negative attitude is persistent and affects the quality of your work. Start by talking with them about their attitude, keeping the focus on how they are affecting the team and your work. Most people who tend to be moody don’t want their moodiness to become a topic of conversation, and will change their behavior.