The definition of insanity is doing the same thing over and over and expecting different results.

Misattributed to various people, including Albert Einstein and Mark Twain. An early occurrence was used as a teaching reference at University of California, Irvine in social science lectures in the later 1960s. Also found in a 1981 text from Narcotics Anonymous.

An earlier version from 1975, spoken during a public talk by Osho | "The mind is always asking you to do something over again, something you have already done so many times before. And every time you see that by doing it nothing is achieved. What else can madness be?" | And later in the same talk | "To be mad is to keep repeating something that has already been seen as useless, as worthless". | Osho, The Great Secret, Chapter #10 | 1975