It has come to be synonymous with pointless protocol or manipulative patter designed to delude. It isn’t any of these things.
Courtesy is simply showing respect for others – even small children and people who have no power or influence. Respect for their human rights. Their bodily integrity. Their views and opinions. Their beliefs and ideas. Their homes and possessions. Their existence.
Therefore, to really be courteous we must first have that respect for everybody – and then show it. Because to be treated with real courtesy is our right, just as to show that courtesy to everyone is our responsibility.
…observe courtesy, for above all it is the prince of virtues…Who is illumined with the light of courtesy…hath indeed attained a sublime station. (1)
(1) Bahá’u’lláh – Tablet of the World