A serious student must learn not to be impatient, to continue steadfastly and to persevere. Conducting oneself with control whether inside or outside the dojang (school). An ability to work within one's capabilities.
Taekwondo is not to be used for aggression, but for defense. This is one reason why a student of Taekwondo must learn self-control while he/she is learning techniques. In class, physical self-control is vital to avoid accidentally harming one's self or one's fellow students.
