I hate saying no to my kids or husband. It makes me feel like I am mean and totally detracts from my efforts to be super mom/wife. But it is increasingly a necessity, because "later," "maybe," and "yes, but its not a promise" only bring on a mirad of questions.
I hate to break promises, because...well, because its a promise and I think that means something...like taking a vow. When promises are made and broken it really hurts. It's not really so much that the promised "thing" or "event" did not materialize, but that the something sacred in the word spoken was defiled.
It is so easy to forget the powerful nature of the spoken word. God spoke and the world was created. We speak and we cause healing and growth or pain and suffering. A wonderful book that looks at this indepth is Words That Hurt, Words That Heal: How to Choose Words Wisely and Well. And so our "yes" ought to be as good as a promise and our "no" be firm as well and we choose when to use them after a moment of reflection. I'm trying to learn, "Ask me again [specify appointed time] when I can give you a thoughtful answer" [so I don't burn dinner again].
If we consider the Theology of the Body as well, we can apply the same principles. Let all that you do be in sync with your thoughts and your soul. The hug I give my child ought to be an authentic condolence, my household tasks true acts of service, and my giving of self a thoughtful endeavor. If I say I am going to do something, then I ought to do it and do it well. (My own mother was very big on this in regard to household chores and management.)
And I am hoping that eventually, as my children grow older, when they read of God's promises, or God whispers some difficult question in their heart, they, like Mary can give their own thoughtful "YES" and it will be life-giving and it will take root deeply.