Why is it easier said than done?
"Yes" forces us to show our hand. Fear of failure, fear of judgment, even fear of success can set in. There's also a level of sacrifice that comes with it. "What do I have to give up in order to do this?" or "What if I over-commit?" There are so many other factors that it can become a juggling act for quite a while.
Why should I do it anyway?
If you want nothing, then do nothing. It's very rare that the dream life comes on its own. Most people have to go out and get what they want out of life.
While we shouldn't automatically say "yes" to everything, we shouldn't automatically say "no" either. Every opportunity that comes our way deserves at least some consideration before making a decision.
Success has no excuses.
Where do I begin?
Start by creating three lists: "What I Do", "What I Want to Do" and "What I've Been Asked to Do."
Now, disregarding what list it's actually in, check off only those things that you'd actually do if there was nothing to hold you back. Cross off all the others that you wouldn't do.
There are no "maybes"; everything is either a "yes" or a "no."
Now take those checked items and write down your "yes" list; posting it where you can see it every day.
This is what every goal is to be measured against; current or new. If it fits, do it; if it doesn't, don't.
That's the true power of "Yes."