“Nobody really cares if you're miserable so you might as well be happy.”

Cynthia Nelms, quoted as "Thought du jour" in "Social Studies" in Globe & Mail July 24, 2009

“I did not so much mind the pessimist who complained that there was so little good. But I was furious, even to slaying, with the pessimist who asked what was the good of good.”

G.K. Chesterton, “Reflections on [The Man Who Was] Thursday” in Gilbert Magazine Vol. 10 #8 (July-August 2007)

“Happy is he who still loves something that he loved in the nursery: he has not been broken in two by time; he is not two men, but one, and has saved not only his soul but his life.”

G.K. Chesterton in Illustrated London News Sept. 26, 1908, quoted in Gilbert Magazine Vol. 10 #2 (Issue 75) Oct.-Nov. 2006

“Everything should be made as simple as possible, but not simpler.”

This quotation is hard to source because it seems to originate with Roger Sessions in 1950. But Sessions said Einstein had said it "in effect" and since then it has been very widely attributed to Einstein because who ever heard of Roger Sessions (I hadn’t; turns out he was a composer) whereas Einstein’s the guy with the giant brain and hairdo to match. The Quote Investigator says while Einstein did express this idea at various times it is probably Sessions who, while deflecting the credit, actually created the concise, beloved and much quoted version above.

“there is no real shame in retreating from an impossible situation or in fleeing from an enemy that seems too powerful to attack.”

Malcolm Cowley, Exile’s Return: A Literary Odyssey of the 1920s.

“You would indeed be fortunate to get this person to work for you.”

A recommended line in a letter of recommendation for a lazy employee (I found it here but do not know where it originated).

“If the real girl is experiencing a real romance, she is experiencing something old, but not something stale.”

G.K. Chesterton “The Real Problem with Sentimental Art” reprinted in Gilbert Magazine Vol. 9 #6