The sentences are from a short story, titled "Light Secrets," by the writer Joseph O'Neill. "Light Secrets" appeared in the January 26, 2026 issue of The New Yorker.
From the narrator of Mr. O'Neill's story:
"Despite my failing memory, I suffer more and more often from excruciating flashbacks in which I relive moments when I said or did something foolish. The worst, most haunting kind of foolishness is unkindness."
I'm mainly focused, as I type Mr. O'Neill's words, on the latter sentence, concerning the realm of unkindness.
It is a subject I have thought about, off and on, through the years.