I used a version of this in my book "Upper West Side Story: A History &
Guide" (Abbeville Press). I got it from the late 19th-century industrialist
and polymath Isaac Leopold Rice, via his daughter Dorothy's memoir,
"Curiouser & Curiouser":

An old man on his deathbed gathered his family to his side. "My sons," he
said, "I have had many troubles in this world. But most of them never
happened."

Of course, Mr. Rice's source is still an open question . . . .

Pete Salwen