But seriously...

The Christian theologians of the first few centuries were serious men. And they did not feel it right that God should be thought of as a laughing God. Laughter is uncontrolled, physical, spontaneous. The divinity is not subject to these constraints. Laughter is too human a phenomenon.

But if it is unthinkable that God should laugh, then neither, then, is laughter appropriate for his creatures. LaugifIng, said John Chyrsostom, distorts the face which is the image of God. Is it a trap of the devil:
Human being laugh and weep, and it is a matter of weeping that they laugh.

It all had to do with an awareness of history. The age in which we live is counted "one of tears, not joy." Around 390AD Chrysostom preached that "this world is not a theatre, in which we can laugh, and we are not assembled together in order to burst into peals of laughter, but to weep for
our sins." A century and a half later, when the Rule of St Benedict was written, it stated "as for coarse jests and idle words or words that lead to laughter, these we condemn with a perpetual ban". The times were clearly for repenting in.

At the heart of this condemnation of laughter was the assertion that "Christ never laughed" — something for those wearing What Would Jesus Do bracelets to think about. The supposed seriousness of Jesus has been a point of agreement by some distinguished friends and foes of Christianity even in the modern era. Philosopher Friedrich Nietzche writes of Jesus, "He knew only tears and the melancholy of the Hebrew...Would that he had remained in the wilderness and far from the good and the just! Perhaps he would have learned to live and to love the earth--and laughter too."