“Yesterday was shaped by Kandinsky's move... This departure is what proves something for me... It is a friendship that overcomes a number of negative items, because the plus side stands firm and, in particular, because there is a link to my productive youth [in Munich].”

As quoted by James Gow, A Short History of Greek Mathematics https://books.google.com/books?id=9d8DAAAAMAAJ (1884)
Arithmetica (c. 250 AD)

The Paris Review interview (1984)
Context: I let characters and symbols emerge from me, as if I were dreaming. I always use what remains of my dreams of the night before. Dreams are reality at its most profound, and what you invent is truth because invention, by its nature, can’t be a lie. Writers who try to prove something are unattractive to me, because there is nothing to prove and everything to imagine. So I let words and images emerge from within. If you do that, you might prove something in the process.

Thomas H. Davenport and J.C. Beck (2001). The Attention Economy: Understanding the New Currency of Business. Harvard Business School Press. p. 20

Source: Bullet

However, negative numbers gained acceptance slowly.
Source: Mathematical Thought from Ancient to Modern Times (1972), p. 185.

Roger Cooke in: The history of mathematics: a brief course http://books.google.co.in/books?id=z-ruAAAAMAAJ, Wiley, 7 October 1997, p. 207.

And it was an icicle just jammed into my chest. That my own mother—and with cause! It was not as if I was the greatest kid in the world. I was a troublemaker! I was a brat! I was a big-mouth pain in the ass! But that my own mother would not understand—at that moment I had what, now at age seventy-two I understand, was an enormous epiphany, which is: I really cannot support it, I cannot bear it, when people laugh at me.
Source: Dreams with Sharp Teeth (2008) https://www.imdb.com/title/tt1018887/ (documentary), at about 28:10.
Context: About being beaten up by bullies as a child.