Why Do We Limit Ourselves and Prevent Ourselves from Living Fully?

"Fear is not my enemy, fear of losing is my enemy" - Rafael Nadal. This quote is something that I think about multiple times a day. It's a quote that makes me think about why I am or am not doing certain things in my life or delaying taking a stand or making a decision. So much of our emotional energy is wasted thinking about hypothetical situations that we make up in our heads. These things keep us either in the past or in the future but most certainly they remove us from the present. Many times my fear of facing things for what they are and allowing them to weigh on me is the cause of stress and anxiety in my life.