My comments:

On Etiquette

Etiquette to society is as cloth (clothes) to human being.  It will be ridiculous if no one wears clothes and this will leads to bad moral.  It will be a tragic for a society to have no etiquette.  In such a society, interactions among its members will be interfered by unwothy (unworthy) conflicts and disputes.  If a society is a train, then etiquette is the track, along which the train can only move forward. (要用虚拟语气) If a society is a VIP car, etiquette is then like the wheels and axles on which the wagon rely to roll (要用虚拟语气).  Without courtesy, even the closest  friends would become deadly enemies and friendly or allied countries would fight each other.  We can find many such examples in human history.  Therefore my advice is that you should pay attention to eqiquette (typo), and avoid doing anything contrary to etiquette so that you will not offend anyone else or make enemies.