No discovery of modern psychology is, in my opinion, so important as its scientific proof of the necessity of self-sacrifice (or discipline) to self-realization and happiness.
Henry C. LinkPsychologically I should say that a person becomes an adult at the point when he produces more than he consumes or earns more than he spends. This may be at the age of eighteen, twenty-five, or thirty-five. Some people remain unproductive and dependent children forever and therefore intellectually and emotionally immature.
Henry C. Link