“A day without laughter is a day wasted.”

Source: Himalayan Lust

La plus perdue de toutes les journées est celle où l'on n'a pas ri.
Maximes et pensées (1805)
Variant translations:
The days most wasted are those during which we have not laughed.
A day without laughter is a day wasted.
While many such expressions have become widely attributed to Charlie Chaplin and a few others, research done for "A Day Without Laughter is a Day Wasted" at Quote Investigator http://quoteinvestigator.com/2011/07/16/laughter-day/ indicate that such expressions date back to that of Chamfort, published in "Historique, Politique et Litteraire, Maximes détachées extraites des manuscrits de Champfort" Mercure Français (18 July 1795), p. 351 http://books.google.com/books?id=N3tBAAAAcAAJ&q=%22pas+ri%22#v=snippet&q=%22pas%20ri%22&f=false Translations of this into English have been found as early as one in "Laughing" in Flowers of Literature (1803) by F. Prevost and F. Blagdon:
: I admire the man who exclaimed, “I have lost a day!” because he had neglected to do any good in the course of it; but another has observed that “the most lost of all days, is that in which we have not laughed;” and, I must confess, that I feel myself greatly of his opinion.

Horatius, st. 70
Lays of Ancient Rome (1842)
Context: When the goodman mends his armor,
And trims his helmet's plume;
When the goodwife's shuttle merrily
Goes flashing through the loom;
With weeping and with laughter
Still is the story told,
How well Horatius kept the bridge
In the brave days of old.

Prologue
The Path of the King (1921)
Context: Generations follow, oblivious of the high beginnings, but there is that in the stock which is fated to endure. The sons and daughters blunder and sin and perish, but the race goes on, for there is a fierce stuff of life in it. It sinks and rises again and blossoms at haphazard into virtue or vice, since the ordinary moral laws do not concern its mission. Some rags of greatness always cling to it, the dumb faith that sometime and somehow that blood drawn from kings it never knew will be royal again. Though nature is wasteful of material things, there is no waste of spirit. And then after long years there comes, unheralded and unlooked-for, the day of the Appointed Time...

Source: The Man Who Studied Yoga (1956), Ch. 5

Non c’è giorno senza tenebre e notte senza luce.

Four Riddles, no. III
Rhyme? and Reason? (1883)