“There's an old saying in Tennessee - I know it's in Texas, probably in Tennessee - that says, fool me once, shame on - shame on you. Fool me - you can't get fooled again.”

Source: On Writing: A Memoir of the Craft

Source: Song No Role Modelz

(Now and Then There's) A Fool Such as I (1952)

Stanley Kunitz (trans.) Story Under Full Sail (New York: Doubleday, 1974) p. 20.

Source: Works and Days (c. 700 BC), line 210.

Source: Flatland: A Romance of Many Dimensions (1884), PART II: OTHER WORLDS, Chapter 15. Concerning a Stranger from Spaceland
Context: There I sat by my Wife's side, endeavouring to form a retrospect of the year 1999 and of the possibilities of the year 2000, but not quite able to shake off the thoughts suggested by the prattle of my bright little Hexagon. Only a few sands now remained in the half-hour glass. Rousing myself from my reverie I turned the glass Northward for the last time in the old Millennium; and in the act, I exclaimed aloud, "The boy is a fool."Straightway I became conscious of a Presence in the room, and a chilling breath thrilled through my very being. "He is no such thing," cried my Wife, "and you are breaking the Commandments in thus dishonouring your own Grandson." But I took no notice of her. Looking round in every direction I could see nothing; yet still I FELT a Presence, and shivered as the cold whisper came again. I started up. "What is the matter?" said my Wife, "there is no draught; what are you looking for? There is nothing." There was nothing; and I resumed my seat, again exclaiming, "The boy is a fool, I say; 3³ can have no meaning in Geometry." At once there came a distinctly audible reply, "The boy is not a fool; and 3³ has an obvious Geometrical meaning."

Source: Getting Things Done: The Art of Stress-Free Productivity

Source: Factotum