You know that employee who is always keen to lend a hand--even when her plate is already filled with one task too many? Chances are you have an "Obliger" in your midst.

Obligers are people who thrive on meeting other people's expectations of themselves, but struggle with their own. They represent one of of four personality types--the others are Upholders, Questioners, and Rebels--identified by author Gretchen Rubin in her book The Four Tendencies. Speaking at the 2018 Inc. 5000 conference in San Antonio, Rubin explained how these personality types are determined by the way people respond to inner and outer expectations, and how they manifest in the workplace.

Questioners, she said, will only meet outer expectations--what other people count on them to do--if it matches their inner beliefs (how they view themselves), Upholders are great at meeting both inner and outer expectations, while Rebels, well, "rebel" against all expectations and resist meeting them.

Obligers are the most common personality type in the world, Rubin said, so odds are you probably have a few of them in your team. Because they're great at keeping up with others' expectations of them, they often make great partners, teammates, and employees. But while there are many benefits to Obliger employees, there's also a heightened risk that they'll burn out from continually saying "yes" to new projects and tasks even when they don't want to do them.

If this goes on for too long, it could lead to something Rubin dubbed "Obliger rebellion," which happens when an Obliger feels disrespected or unheard, and their defense mechanism is to shun a co-worker or quit their job. As a manager, you need to make sure you are always aware of how your Obliger employees are doing, she said.

Rubin, who is a self-proclaimed Upholder, cited an example from her own work experience. She tends to respond to emails during the weekend, she said, simply because that's when she has time to do it. Although she doesn't expect anyone to reply at that time, one of her Obliger employees grew increasingly resentful because she felt the need to respond right away and it interfered with her weekend. The solution, Rubin said, was to use a delayed delivery system. Now when Rubin writes an email on Saturday, it will get sent Monday morning.

"It's not that one person is right and one person is wrong," she explained. "It's about how we can create an environment that works for both of us, so that we can both thrive."

If you have Obliger employees, keep an eye on their workload and effort to distribute projects evenly, Rubin recommended. Encourage them to use their vacation time too, she added, by creating the expectation that they need to take time off to recharge.