“Sometimes something catastrophic can occur in a split second that changes a person's life forever; other times one minor incident can lead to another and then another and another, eventually setting off just as big a change in a body's life.”

https://archive.org/stream/GuillaumeATheLifeOfMuhammad/Guillaume%2C%20A%20-%20The%20Life%20of%20Muhammad_djvu.txt

Source: An Introduction to Cybernetics (1956), Part I: Mechanism, p. 9: Chapter 2 Change, lead paragraph.
Context: The most fundamental concept in cybernetics is that of "difference", either that two things are recognisably different or that one thing has changed with time. Its range of application need not be described now, for the subsequent chapters will illustrate the range abundantly. All the changes that may occur with time are naturally included, for when plants grow and planets age and machines move some change from one state to another is implicit. So our first task will be to develop this concept of "change", not only making it more precise but making it richer, converting it to a form that experience has shown to be necessary if significant developments are to be made.

Source: The Book Thief

Variant: It is one of the beautiful compensations of life that no man can sincerely try to help another without helping himself.

"Another Perfect Catastrophe", The Ponzi Scheme (May 5, 1998).
Lyrics, Firewater

Book B (sketchbook), c 1967: as quoted in Jasper Johns, Writings, sketchbook Notes, Interviews, ed. Kirk Varnedoe, Moma New York, 1996, p. 62
1960s

"Quo Vadimus?" http://books.google.com/books?id=vvEvAAAAMAAJ&q=%22Did+it+ever+occur+to+you+that+there's+no+limit+to+how+complicated+things+can+get+on+account+of+one+thing+always+leading+to+another%22&pg=PA34#v=onepage, The Adelphi (January 1930)