Who said "The secret source of humor is not joy but sorrow."?

This quote is attributed to Robert Frost.

The secret source of humor is not joy but sorrow. - Robert Frost

"The secret source of humor is not joy but sorrow."

Robert Frost Humor

Poet American 1874–1963

"Two roads diverged in a wood, and I took the one less traveled by."

"The only way out is through."

"Good fences make good neighbors."

"Fire and Ice."

"Never underestimate the power of a good laugh."

"Laughter is the best medicine."

"A good laugh is the best medicine."

"Laughter is contagious and wonderful."