“Those who are in a hurry know that they can easily slip into carelessness. And carelessness easily invites woe and disaster.”
Related quotes

“Monotheism is easily the greatest disaster to befall the human race.”
Appendix
1980s, At Home (1988)
Context: I regard monotheism as the greatest disaster ever to befall the human race. I see no good in Judaism, Christianity, or Islam — good people, yes, but any religion based on a single... well, frenzied and virulent god, is not as useful to the human race as, say, Confucianism, which is not a religion but an ethical and educational system that has worked pretty well for twenty-five hundred years. So you see I am ecumenical in my dislike for the Book. But like it or not, the Book is there; and because of it people die; and the world is in danger.

“Worries find you easily enough without inviting them.”
Source: Dark Places

To My People (July 4, 1973)

The Pursuit of Simplicity (1981), p. 151
Variant: Total security has never been available to anyone. To expect it is unrealistic; to imagine that it can exist is to invite disaster. I believe the most important aim for humanity at present is to avoid war, dictatorship, and their awful consequences.
Better a Shield Than A Sword : Perspectives On Defense And Technology (1987), p. 241
Context: The preservation of peace and the improvement of the lot of all people require us to have faith in the rationality of humans. If we have this faith and if we pursue understanding, we have not the promise but at least the possibility of success. We should not be misled by promises. Humanity in all its history has repeatedly escaped disaster by a hair's breadth. Total security has never been available to anyone. To expect it is unrealistic; to imagine that it can exist is to invite disaster. What we do have in our technological capacities is an opportunity to use our inventiveness, our creativity, our wisdom and our understanding of our fellow beings to create a future world that is a little better than the one in which we live today.

1910s, The Progressives, Past and Present (1910)

U.S. House of Representatives, September 12, 2001 http://www.house.gov/paul/congrec/congrec2001/cr091201.htm
2000s, 2001-2005

2016, Memorial Service for Fallen Dallas Police Officers (July 2016)
Context: I've seen how a spirit of unity, born of tragedy, can gradually dissipate, overtaken by the return to business as usual, by inertia and old habits and expediency. I see how easily we slip back into our old notions, because they’re comfortable, we’re used to them. I’ve seen how inadequate words can be in bringing about lasting change. I’ve seen how inadequate my own words have been. And so I’m reminded of a passage in *John’s Gospel [First John]: Let us love not with words or speech, but with actions and in truth. If we’re to sustain the unity we need to get through these difficult times, if we are to honor these five outstanding officers who we’ve lost, then we will need to act on the truths that we know. And that’s not easy. It makes us uncomfortable. But we’re going to have to be honest with each other and ourselves.