I can feel guilty about the past, apprehensive about the future, but only in the present can I act. The ability to be in the present moment is a major component of mental wellness.
Source: In The Speaker's Electronic Reference Collection, AApex Software, 1994.
-- Abraham Maslow, (Apr 1 1908-1970), US psychologist, philosopher; His self-actualization theory of psychology argued that the primary goal of psychotherapy should be the integration of the self.