“I failed eating, failed drinking, failed not cutting myself into shreds. Failed friendship. Failed sisterhood and daughterhood. Failed mirrors and scales and phone calls. Good thing I'm stable.”

Even Cowgirls Get the Blues (1976)
Context: So you think that you're a failure, do you? Well, you probably are. What's wrong with that? In the first place, if you've any sense at all you must have learned by now that we pay just as dearly for our triumphs as we do for our defeats. Go ahead and fail. But fail with wit, fail with grace, fail with style. A mediocre failure is as insufferable as a mediocre success.

Of his father
Sons Come and Go, Mothers Hang in Forever (1976)

Source: The Book Of Counted Sorrows

Source: Antifragile: Things That Gain from Disorder (2012), p. 79

(A.J. Broomhall. Hudson Taylor and China’s Open Century, Book Five: Refiner’s Fire. London: Hodder and Stoughton and Overseas Missionary Fellowship, 1985, 175).

The Ballot or the Bullet (1964), Speech in Cleveland, Ohio (April 3, 1964)
Context: You and I in America are faced not with a segregationist conspiracy, we’re faced with a government conspiracy. Everyone who’s filibustering is a senator—that’s the government. Everyone who’s finagling in Washington, D. C., is a congressman—that’s the government. You don’t have anybody putting blocks in your path but people who are a part of the government. The same government that you go abroad to fight for and die for is the government that is in a conspiracy to deprive you of your voting rights, deprive you of your economic opportunities, deprive you of decent housing, deprive you of decent education. You don’t need to go to the employer alone, it is the government itself, the government of America, that is responsible for the oppression and exploitation and degradation of black people in this country. And you should drop it in their lap. This government has failed the Negro. This so-called democracy has failed the Negro. And all these white liberals have definitely failed the Negro.

Attributed to Trench by Prof. Connington; reported in Hoyt's New Cyclopedia Of Practical Quotations (1922), p. 253.

Wooden only repeated a common aphorism (e.g. Interview on Charlie Rose, reported by Bill Walton), which was already in circulation as early as the 1920s, when he was a youth. http://www.google.com/search?hl=en&tbs=bks%3A1%2Ccdr%3A1%2Ccd_min%3AJan+1_2+1900%2Ccd_max%3ADec+31_2+1930&q=%22fail+to+prepare%22+%22prepare+to+fail%22
Misattributed