I recently wrote an article entitled Why it’s OK to say NO and 3 tips for doing it gracefully. Check it out.
The more I deal with people who struggle to maintain and enforce their boundaries around their own time and energy, the more I have come to appreciate that we MUST be able to say no if we are to maintain our own health and well-being. There is nothing more stressful than feeling like you have no control over the demands in your life. Without the ability to say no, you are completely at the mercy of the requests and demands of others. This is a recipe for burn-out.