Fear is the most powerful single factor that deprives you of being able to achieve your full potential. You experience it most often as a result of your own thoughts and emotional visions, rather than actual real world causes. In other words, you become fearful of a fantasy – something that doesn’t exist.
http://www.marcandangel.com/2013/04/10/5-ways-to-step-forward-when-youre-scared/