Every “yes” you utter is a tradeoff. By saying “yes” to one thing, you’re saying “no” to something else. Saying “yes” to staying late at work, for example, might mean saying “no” to the gym or to time spent with your family. Research conducted at the University of California, San Francisco, showed that the more difficulty you have saying “no,” the more likely you are to experience stress, burnout and even depression. Saying “no” is indeed a major challenge for many people. No is a powerful word that you should not be afraid to wield. When it’s time to say “no,” avoid phrases such as I don’t think I can or I’m not certain . Saying “no” to a new commitment honors your existing commitments and gives you the opportunity to successfully fulfill them. When you learn to say “no,” you free yourself from unnecessary constraints and free up your time and energy for the important things in life.