The question often comes up in late-night conversations with friends: Do you have any regrets about decisions you’ve made in your life? Even when taking into account the most unfortunate consequences I’ve faced for things I’ve done, my standard answer has always been, “No, since I don’t know what would have happened if I’d done otherwise. It might have been worse.”

That principle only goes so far, though. Although it allows me to feel comfortable with the general path my life has taken, it doesn’t eliminate the sting of tiny moments when, through selfishness or thoughtlessness or negligence, I’ve hurt someone else. How many times I’ve wished that I could hit the Stop button, rewind a bit, and redo the last few seconds!

My college roommate Jay once told me that I had “an overdeveloped sense of loss.” To the extent that’s true, it probably started on a spring day when I was a young child. My mother had never been a morning person — she was pretty much unapproachable until she’d had her coffee and put on her makeup. But on this one morning, she somehow woke up in a good mood. She emerged from her bedroom smiling, and remarked on how nice a day it was. She had a lightness that I’d never seen before.

I, meanwhile, had been privately working myself into a snit about some injustice I had suffered — something my sister had done to me, or some chore I’d been tasked with that I shouldn’t have had to do. Whatever the cause of my pique, seeing my mother so happy caused me to confront her with an aggrieved, whiny outburst. Her sunny aura vanished instantly, and she reverted to her usual morning grumpiness and irritation as she dealt with my complaint.

Immediately, I felt a huge wave of guilt and remorse. In killing her rare good mood, I felt like a murderer — like a hunter who had slaughtered a unicorn. But I was a child, not yet old enough to know how to back off and apologize, and so I continued to gripe and whine, even while seeing the damage I’d caused and knowing that it hadn’t been necessary.

I still grieve for that lost ray of sunshine. If “grieve” sounds like hyperbole, I have to assure you that it isn’t. Even though I’ve been able to forgive myself for the incident, the emotions associated with it are still fresh.

Another such moment occurred when I was in college. The feelings in this case are not as intense, but just as long-lasting.

It was a warm summer night, the kind in which the day’s oppressive humidity is relieved by a mild breeze, and clouds part to reveal the stars. Princeton has no classes during the summer, so the campus population was small: just a few grad students and those of us undergrads who had summer jobs. (I was working for the campus tour service.) There would be occasional evening activities at the graduate college, such as outdoor concerts and film showings. This was one of the latter — a showing of the classic “Treasure of the Sierra Madre,” which I’d never seen and had long wanted to.

I liked to arrive early to such events, to find a good seat and get settled in. I found myself sitting near a young woman whom I’d never seen before. She and I began to chat, and in the fresh embrace of the summer air, I immediately felt at ease. Think of how rare those occasions are when you meet somebody and instantly hit it off — no self-consciousness, no posing. This was one of those occasions, where we felt each other’s warmth and delighted in each other’s openness. We didn’t talk once the film began to roll, but my enjoyment of it was acutely enhanced by having her nearby.

When the movie ended and we got up to go our separate ways, I wanted to tell her how much I enjoyed her company, and — perhaps — find a way to see her again. But how to find the words? “I’ve really enjoyed getting to know you, Carol,” I said.

“Carol?” she replied, her eyes narrowing. “My name is Susan.”

Actually, I don’t know whether her name was Susan; I just made that part up. That’s the point — I remembered her as Carol, but I had it wrong. And that was the end of our rapport; the door slammed shut. I watched her walk off into the night.

Who knows whether anything would have come of that chance meeting? Summer nights have strange effects on people, and we might not have fallen under the same spell if we were to get together a second time. Maybe it’s best that the evening ended the way it did, with the pleasant memory of our brief time together.

But having called her by the wrong name in such a vulnerable atmosphere, I felt, and still feel, like I committed an act of violence. Not only did I insult her, but I had negligently put a sudden end to a precious moment of connection. From such small acts come the greatest regrets.