Let's face it, there's always someone in the group who is constantly the target of complaints or is asked to take on more labor.

When that person is you, it can be difficult to tell a friend, colleague, or employer to back off.

But there is a way.

The trick may lie in how you tell someone "no," according to Mental Floss.

If you want to set boundaries, simply say that you don't do something, rather than you can't.

For example, if your boss asks you if she can send you a project after work to do at home, the best way to turn her down is to say something like, "Sorry, I don't answer work emails after 5."

This same approach applies to friends who make unreasonable demands on your time or energy.

Letting your preferences be known in this way leaves "no room for debate," according to Mental Floss.

The advice is based on a 2012 study that found that the phrase "I don't" is more effective at enhancing goal-directed behavior — such as motivating yourself to exercise daily — and can be applied to many aspects of your life.

Finding a way to say no is about as difficult for many people as gracefully inserting the word "antidisestablishmentarianism" into a casual conversation.

There is guilt associated with rejecting another person's request and fear that they may resent you for it.

But setting boundaries can ultimately be what's best for your health.

People who answer work emails after hours were more prone to have "worse sleep, higher levels of burnout, and more health-related absences from work," according to a 2015 study reported by Time magazine.

Learning to say no to people can be difficult, whether they're family, friends, or employers.

But making sure that your energies aren't drained by the emotional or physical demands of others can allow you to engage more fully and happily with others.