“It is wrong to blame anyone for failing to forecast accurately in an unpredictable world. However, it seems fair to blame professionals for believing they can succeed in an impossible task.”

The Benn Heresy (1982).
1980s

Source: Bleak Seasons (1996), Chapter 77 (p. 212)

TV Interview for Yorkshire Television Woman to Woman (2 October 1985) http://www.margaretthatcher.org/document/105830
Second term as Prime Minister
Context: All my upbringing was to instill into both my sister and I a fantastic sense of duty, a great sense of whatever you do you are personally responsible for it. You do not blame society. Society is not anyone. You are personally responsible and just remember that you live among a whole lot of people and you must do things for them, and you must make up your own mind. That was very very strong, very strong. I remember my father sometimes saying to me if I said: “Oh so and so is doing something; can't I do it too?” You know, children do not like to be different. “You make up your own mind what you are going to do, never because someone else is doing it!” and he was always very stern about that. It stood one in good stead.

Source: Cruddy

Source: Aleph (2011)
Context: It’s always easy to blame others. You can spend your entire life blaming the world, but your successes or failures are entirely your own responsibility. You can try to stop time, but it’s a complete waste of energy.

Variant: You can get discouraged many times, but you are not a failure until you begin to blame somebody else and stop trying.

from "Having Regulations—A Memorandum" in The Complete Works of Han Fei Tzu, Volume I, Arthur Probsthain, London, 1939. Translated by W.K. Liao.

This is a rhyme used in Merrick's sideshow pamphlet, and which he is said to have often repeated, and used to sign his letters, followed by a quotation from "False Greatness" by Isaac Watts, first published in Horae Lyricae (1706) Bk. II:
If I could reach from pole to pole
or grasp the ocean with a span,
I would be measured by the soul
The mind's the standard of the Man.