From Christmas Cheer by Angus Reach, James Hannay and Albert Smith, 1856.

"If you feel like laughing, go as far as you like."  From The Book of Spice by "Ginger" a.k.a. Wallace Irwin, 1906.

Thanks to Malo for the doodle!

We learn this from Percival Leigh's The Comic English Grammar: A New and Facetious Introduction to the English Tongue (1840).

"You have to be able to laugh at anything and everything.  The statues of the Buddha all smile, and not without reason, whilst the Christian saints are all bathed in tears.  If people would smile more often, there would probably be fewer wars."
—Gustav Meyrink, The Green Face

"In the psychological development of the child, there is a step-by-step progression from the primal smile to the smile of embarrassment, joyful laughter, laughter at a comic situation, laughter in a group, aggressive laughter at an outsider, and finally (a somewhat depressing climax) the laugher of Schadenfreude.  ... [A]t each step laughter signifies an experience of relief (Entlastung), both physically and psychologically."
—Peter Berger, Redeeming Laughter: The Comic Dimension of Human Experience (1997)

From Prof. Oddfellow's sketchbook: