 Anything conflicting with reason in human action is vicious. It is against reason for a man to be burdensome to others, by never showing himself agreeable to others or being a kill-joy or wet blanket on their enjoyment. And so Seneca says, “Bear yourself with wit, lest you be regarded as sour or despised as dull.” Now those who lack playfulness are sinful, those who never say anything to make you smile, or are grumpy with those who do (2a2ae, Q. 168, Art. 4).