excellence of manners or social conduct; polite behavior
an introductory act or step; leading action
one's personal, responsible decision
high respect, as for worth, merit, or rank
A person without courtesy is one who, for example, would generate a mess in a shared space and leave it for days until someone else with initiative cleans it up. History has proven that the first person who lack courtesy also lack initiative. This person, in my view, also lacks honor.
Of course, it would probably be prime for someone to tell that person of the things he/she lacks. However, does not society, God, and dogma expect us to act our age, or at least act with courtesy, initiative, and honor? What then, aside from a chemical imbalance, disorder or lack of morality, which the described person does not have, would a person's excuse be?