The way it was explained to me is "one ah' shit wipes out a thousand atta boys."
I was told this by a mentor in the space programs but when I just did a search, it seems it has been talked here on medium as well. I guess it is a common aphorism.
https://medium.com/@batesdon1/one-aw-shit-cancels-a-1-000-atta-boys-who-said-it-first-and-so-what-1e987444dd7b
TEK