Customs and traditions keep us from offending our hosts.
Table manners ensure our opinions are heard and not quickly discounted.
Common courtesies build trust and respect.
Grammar eases the reader of even bad news.
Conventions allow for agreements even while in conflict or war.
All of these can be understood, taught, studied and even mastered.
In a connected world where little seems uncontrollable, all of these give us a foot up.