Picked up this article from an internal productivity newsletter.

“No” can sometimes seem a very difficult thing to say. Have you ever noticed, however, that kids say “No” all the time? My 8-year-old, for example, is really really good at it. I think “No” was one of the first words out of her mouth. So how do we lose the ability to say “No?”

Well, we don’t lose it, exactly. We give it up for something we think is more important. For one, it can be a desire to please that keeps us from saying “No.” Many of us grow up to be people pleasers, and we substitute lots of ways to be agreeable and keep other people happy instead of simply saying “No.” 

Read more "The Power and Freedom of Saying No" (McGhee Productivity Solutions)