Whether there is a sin in lack of mirth?

Objections

Objection 1 : It would seem that there is no sin in lack of mirth. For no sin is prescribed to a penitent. But Augustine speaking of a penitent says (De Vera et Falsa Poenit. 15) [*Spurious]: "Let him refrain from games and the sights of the world, if he wishes to obtain the grace of a full pardon." Therefore there is no sin in lack of mirth.
Objection 2 : Further, no sin is included in the praise given to holy men. But some persons are praised for having refrained from mirth; for it is written (Jer. 15:17): "I sat not in the assembly of jesters," and (Tobias 3:17): "Never have I joined myself with them that play; neither have I made myself partaker with them that walk in lightness." Therefore there can be no sin in the lack of mirth.
Objection 3 : Further, Andronicus counts austerity to be one of the virtues, and he describes it as a habit whereby a man neither gives nor receives the pleasures of conversation. Now this pertains to the lack of mirth. Therefore the lack of mirth is virtuous rather than sinful.