Every one is familiar with the phenomenon of feeling more or less alive on different days. Every one knows on any given day that there are energies slumbering in him which the incitements of that day do not call forth, but which he might display if these were greater. . . . Compared with what we ought to be, we are only half awake.
— William James, Prescription for a Long and Happy Life by Dov Peretz Elkins