“People are more than one thing. Warlocks, no less. I would not even hesitate to say that Malcolm once did much good, before he did evil. It is one of the great lessons of growing up, learning that people can do both.”

From 'Om man så må sige – 350 Dronning Margrethe-citater', quoted in English here http://trondni.blogspot.co.uk/2012/11/new-books-wit-and-wisdom-of-margrethe-ii.html.
Society

Source: Cakes and Ale: Or, The Skeleton in the Cupboard (1930), p. 14

Address at the Conference on Cosmic Design, American Association for the Advancement of Science, Washington, D.C. (April 1999)
This comment is modified in a later article derived from these talks:
:Frederick Douglass told in his Narrative how his condition as a slave became worse when his master underwent a religious conversion that allowed him to justify slavery as the punishment of the children of Ham. Mark Twain described his mother as a genuinely good person, whose soft heart pitied even Satan, but who had no doubt about the legitimacy of slavery, because in years of living in antebellum Missouri she had never heard any sermon opposing slavery, but only countless sermons preaching that slavery was God's will. With or without religion, good people can behave well and bad people can do evil; but for good people to do evil — that takes religion.
:* "A Designer Universe?" at PhysLink.com http://www.physlink.com/Education/essay_weinberg.cfm

To Leon Goldensohn, May 24, 1946, from "The Nuremberg Interviews" by Leon Goldensohn, Robert Gellately - History - 2004 - Page 71

Memorabilia IV.8.8
Xenophon

Jose Mourinho, 2009. http://www.theguardian.com/football/2009/jul/31/sir-bobby-robson-tributes

Source: Quartered Safe Out Here (1992), p. 54.

Variant: A learning experience is one of those things that says, 'You know that thing you just did? Don't do that.
Source: Interview in The Daily Nexus (5 April 2000), reprinted in The Salmon of Doubt

1975 interview https://mises.org/library/hayek-meets-press-1975 on "Meet the Press."
1960s–1970s