Thomas Aquinas

“ It belongs to temperance to curb pleasures of the senses. But this virtue regards the pleasures of fellowship, which have their origin in the reason, in so far as one man behaves becomingly towards another. Such pleasures need not to be curbed as though they were noisome. ”

“ Therefore this kind of friendliness is not a virtue.
Objection 3: Further, virtue "observes the mean according as a wise man decides" (Ethic. ii, 6) . Now it is written (Eccles. 7:5) : "The heart of the wise is where there is mourning, and the heart of fools where there is mirth": wherefore "it belongs to a virtuous man to be most wary of pleasure" (Ethic. ii, 9) . Now this kind of friendship, according to the Philosopher (Ethic. iv, 6) , "is essentially desirous of sharing pleasures, but fears to give pain." Therefore this kind of friendliness is not a virtue. ”

“ Hence there is no dissimulation in this: because we do not show them signs of perfect friendship, for we do not treat strangers with the same intimacy as those who are united to us by special friendship. ”