«In his essay “On Duties”, Cicero remarked that nobody, to his knowledge, had yet set down the rules for ordinary conversation, though many had done so for public speaking.
He had a shot at it himself, and quickly arrived at the sort of list that self-help authors have been echoing ever since.
The rules we learn from Cicero are these:
speak easily but not too much, especially when others want their turn;
do not interrupt;
deal seriously with serious matters and gracefully with lighter ones;
never criticise people behind their backs;
stick to subjects of general interest;
do not talk about yourself;
and, above all, never lose your temper.»
– “The art of conversation“, The Economist, Dec 19th 2006.