“Compared with what we ought to be, we are only half awake.  Our fires are damped, our drafts are checked.  We are making use of only a small pert of our possible mental and physical resources.  … The human individual thus lives usualy far within his limits; he posseses powers of various sorts which he habitually fails to use.  He energizes below his maximum, and behaves below his optimum.   … Either some unusual stimulus fills them with emotional excitement, or some unusual idea of necessity induces them to make an extra effort of will.  Excitements, ideas, and efforts in a word, are what carry us over the dam.”

— William James