Now a man who is without mirth, not only is lacking in playful speech, but is also burdensome to others, since he is deaf to the moderate mirth of others.
 Thomas Aquinas, Summa Theologica (1274). copy citation

add
Author Thomas Aquinas
Source Summa Theologica
Topic speech mirth
Date 1274
Language English
Reference
Note Translated by Fathers of the English Dominican Province
Weblink http://www.gutenberg.org/cache/epub/18755/pg18755-images.html

Context

“[*Martin of Braga, Formula Vitae Honestae: cap. De Continentia] says (De Quat. Virt., cap. De Continentia) : "Let your conduct be guided by wisdom so that no one will think you rude, or despise you as a cad." Now a man who is without mirth, not only is lacking in playful speech, but is also burdensome to others, since he is deaf to the moderate mirth of others. Consequently they are vicious, and are said to be boorish or rude, as the Philosopher states (Ethic. iv, 8) . Since, however, mirth is useful for the sake of the rest and pleasures it affords; and since, in human life, pleasure and rest are not in quest for their own sake, but for the sake of operation, as stated in Ethic.” source