This is an interesting perspective for me to read at this time in my life (middle aged woman) as I surrounded by articles and 'experts' telling me I need to learn to say "NO!". It is surely a fine line to walk. I agree that saying 'no' is often a way of saying no to life and really living it. The answer is of course, to be conscious and take a breath before answering and really understand what your 'yes' or your 'no' will mean in your life and someone elses as well.
Happy Holidays! Peace & Love!