Everyone has a responsibility to not only tolerate another person's point of view, but also to accept it eagerly as a challenge to your own understanding. And express those challenges in terms of serving other people.
Psychologically 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 a the age of eighteen, twenty-five, or thirty-five. Some people remain unproductive and dependent children forever and therefore intellectually and emotionally immature.