Some people have a harder time than others saying no.  In this wonderful article from tinnybuddha.com, learn why it can be a good thing to say no and what the benefits are.  I hope you enjoy!
The Halfhearted Yes: Why We Don’t Say No and How to Start
Some highlights are below…

• “How many of us take what is handed to us, follow what is put in front of us or say yes to things that don’t really align with who we are or what we want in our lives?”
• “If you say yes to everything, never discerning the right yes for you, what difference does it make what you’re saying yes to? Your yes loses its authority.”
• “Learning the power of the word no is about learning the power of discernment and becoming deliberate in your choices. You have to get rid of the old before you can take on the new. You have to say no to the things that don’t serve you to make room for the yes in your life that does.”
• “Take some time to consider what you are saying yes to. Ask yourself, ‘is my heart in this? Or can I let this go to make room for something that matters more?’”