"I have known sorrow—therefore I May laugh with you, O friend, more merrily Than those who never sorrowed upon earth And know not laughter's worth. I have known laughter—therefore I May sorrow with you far more tenderly Than those who never guess how sad a thing Seems merriment to one heart's suffering."
January 1, 1970
https://en.wikiquote.org/wiki/Laughter