In the cognitive sciences there is a phenomenon known as the Pygmalion effect.
Also known as the Rosenthal effect for one the psychologists who discovered it, the phenomenon is simple enough: It reveals that higher expectations lead to better performance. The phenomenon is more than a theory; it has been demonstrated in the lab.
So why don't we expect more from ourselves?
This can be especially difficult if we're already good at something, since then we can have difficulty imagining how much better we could be.
The result is that we limit our expectations, which in turn is how we limit our disappointments. If we expect much, we are often disappointed. To avoid that, we lower our expectations. He or she who expects little and gets little is never disappointed.
One of the keys to continual improvement is the willingness to risk disappointment, to see disappointment not as a bad thing to be avoided but as proof positive we are aiming higher and striving to get better.
"The Potential Principle" by author Mark Sanborn is about unlocking your imagination to pursue more of your potential. And when you do that, your best just keeps getting better.