In our Coping group, one of the things we work on is interpersonal effectiveness. Interpersonal effectiveness has three parts--getting what your want, or your objectives; keeping the relationship intact; and keeping self-respect. Trying to balance all three of these at the same time takes tremendous skill for many of us.
One of the things people struggle with is saying no to others. We worry people won't like us, will see us as selfish, hard to get along with, uncaring, etc.
I found an article a few months ago that I'd like to share. It's a long read, but it offers good information about The Power of No.
One of my favorite parts of the article was:
"How much No is too much? Who turns down a needy friend to tend one's own garden? Where is the line between self actualized and selfish? Who refuses to lend support to the modest effort of a group of friends? What is the boundary between important principles and stubborn oppositionalism?
As a general guideline, five situations benefit from increasing strength to say No."
The article goes on to describe these situations and then offers helps to learn to say "no" when needful.