It’s important to look at your pattern for being. It often comes from the need to be wanted, the desire to be helpful or the importance of being a team player. Saying “Yes” when you want to say no can wreak havoc to your mental and physical well-being.  What prevents you from saying “No” is your beliefs. See if any of the following resonate with you and take a few minutes to assess and clear some core issues so you can be able to say “No” effectively and without guilt.
If I say “No” the other person will think I am lazy or incompetent.  You don’t have to prove your worth by always saying yes. What if you could change your position on saying “No” as a way of demonstrating that you are being strategic by prioritizing what is most important? What if you focus on “quality” rather than quantity? What if by saying “No” you can better keep those commitments you’ve already made?
If I say “No” I will hurt the other person’s feelings and it will undermine the relationship.  If your relationships are important to you, try thinking about how a “No” would relieve resentments that build up by you always saying “Yes”.
I don’t say “no” to work because it’s what gives me self-worth.  If you  are driven by achievement, it’s very easy to keep taking on more because “being productive” and “checking off the to-do list” is the area where you feel most competent and worthy.  Try this mindset shift:  What if you were able to achieve your goals better by focusing on fewer things?  It’s a fact that over-focus on work makes you less productive in the long run. Start thinking about achievement goals in other areas of your life and you will be happier and more content.
I don’t say “no” because I get my self-worth from being helpful to others.  If your sense of identity is based on “giving” or taking care of others’ you may find it extremely difficult  to say “No”. If you are always out there doing, you  will not be able to serve those who are most important to you. You can’t give from an empty cup.
Breaking the Cycle
Close your eyes, let go of everyone else’s demands and make a simple decision to do something you truly want.  Next time you make a choice to say no, simply explain, without an apology, that you have chosen not to participate. State your decision and move forward. You might be surprised at how well everyone takes it and you’ll discover a sense of freedom that you probably haven’t felt for a very long time.
Here’s the Secret 
Get a 3 x 5 card and write the following:
“I appreciate you asking me to ____________________. I trust you’ll understand that I cannot add another thing to my calendar.”
Whatever else you might feel compelled to say (like “I’m sorry” or “because”), don’t. Just be silent, let the other person talk and if they ask you again, read what’s on the card. They’ll get it.
Put the card by the phone or carry it with you, or better yet memorize it and practice with someone who will support you. Perhaps both of you can practice saying no to one another.
Be well and enjoy the holidays!