The Five Reasons Why You Are Not Fulfilling Your Potential. - Stepcase Lifehack
http://www.lifehack.org/articles/productivity/the-five-reasons-why-you-are-not-fulfilling-your-potential.html

1.) You do not have enough belief in yourself. 2.) You do not measure yourself up against written goals. 3.) You are too comfortable where you are. 4.) You are lazy. 5.) You are not mixing with high achievers.