Common Courtesy is an oxymoron.
Courtesy is the standard of behaviour displayed by Courtiers at a Royal Court. It is elitist and never common.
Courtesy is the etiquette and the manner of the Aristocratic upper classes not the common people.
Courtesy is what common people often aspire to because it is not common to most people.
Common courtesy is often seen as the behaviour required of a Gentleman.
Acting like a Gentleman requires me to be ‘Gentle’ rather than Courteous.
Attaining ‘Gentleness’ is the state of being ‘Powerful yet Accepting’ and being ‘Authoritative yet Allowing’.
Being Courteous is behaving in a manner fit for a royal audience as instructed by a royal courtier.
Being Courteous is being humble and deferring to the Sovereign and the Crown. It is obeying the rules and traditions of that Dominion.
Being Common is behaving in a manner and to a standard of the majority of the populus who are the Common People.
Being Common in the presence of Royalty is seen as arrogant and rude.
In the presence of Royalty I can choose Courtesy, Common-ness or Gentleness.