The Principal Doctrines of Epicurus is a 3rd-century outline of Epicurean philosophy.  This bullet point is so consistent with my posts on friendliness, social intelligence, and the Bubble that I feel compelled share it.

He who desires to live
in tranquility with nothing to fear from other men ought to make
friends.  Those of whom he cannot make
friends, he should at least avoid rendering enemies; and if that is not in his power,
he should, as much as possible, avoid all dealings with them, and keep them aloof,
insofar as it is in his interest to do so.