Knowing how to nicely say "no" is an important part of asserting yourself and setting boundaries. When you constantly say "yes" to things you don't want to do, you may find yourself in challenging and stressful situations. When saying "no," there are plenty of ways to reframe your decision in a polite manner. By coming off professionally, your coworkers or clients may respect your decision and have a better understanding of your reasoning. As an employee, you have the agency to say "no," but knowing how to do so nicely and/or professionally can make it much easier to do and add less stress to the job.