Once bitten, twice shy
The origin of this almost Darwinian principle is now lost to us but the concept of avoiding painful experiences is most certainly very ancient. William Caxton in the 15th century gives the conceptual origin as Aesop’s Fables (c.550 BC). The principle behind it appears in many different forms and languages from antiquity but the exact phrase, ‘once bitten, twice shy’ is first cited in English only from the late 19th century from the little-known writer G.G. Northall in his book Folk Phrases of the Four Counties published in 1894, but the title of his book indicates that the expression is much older.