Sometimes a seemingly trivial comment will lodge in our brain and start to fester, ultimately exhibiting a shelf life equal to that of pemmican or granite.

A friend once called to tell me that she wanted to introduce me to a kingpin in our mutual industry. We’ll be sitting at the bar of the Peninsula Hotel, she said. Just hanging out. Totally casz. He knows your work and would love to meet you. He has a dinner at 8, so let’s say 6? 6:30? Just the three of us. I’m wearing jeans. You’ll love him. Maybe try to be a little more effusive than you normally are, Henry?

Lo, the unwitting swipe and its remarkable afterglow. It’s the gift that keeps on giving. It’s the conversational equivalent of fingernails on a corpse. It’s a song whose title and lyrics employ the phrase “let it go” 13 times. One day you’re brimming over with gratitude for having a work buddy like Theresa, someone who can roll with the punches and who you can share a laugh with. The next you’re wondering what she could have possibly meant by the phrase “your bi-curious haircut.”

Indeed, 18 years after the incident with my friend, whenever I get together with work colleagues or potential employers, a little voice inside my head asks, “Am I pouring it on thick enough?”

Wendy Behary, a licensed clinical social worker, said she once had a male patient who made an obscure literary reference during a therapy session. “He looked at my puzzled reaction and asked, ‘Do you read anything other than psychology books?’” she said. “His tone was gentle, it wasn’t mean or accusatory, but it hung for a while. I started cursing under my breath. Later, I went through my library, looking for my copy of ‘Hamlet.’ I thought, ‘I’ll recite a “Hamlet” soliloquy when I see him next!’ My colleagues and my mentor just stared at me, wondering why I was so triggered. I was having this little war inside my brain. ‘How dare he try to say he knows me!’”

Rajiv Satyal is a stand-up comic who lives in Los Angeles. But 11 years ago, he was living in his hometown, Cincinnati, where he worked at Procter & Gamble as a marketer from ages 24 to 30. During a conversation in 2005 with his younger brother Vikas about Vikas’s future, Mr. Satyal was the recipient of the statement: “Or I could be like you. Someone who gave up on his dreams.”

Mr. Satyal said: “Had it been a fight, or had he tried to sit me down for a talk, I would’ve said something. But he just laid it in there, flat. It moved me three time zones across the country, from Cincinnati to Los Angeles.” Mr. Satyal now performs weekly at the Laugh Factory in the Hollywood Hills West neighborhood, and has opened for Dave Chappelle and Tim Allen.

When our interlocutors’ statements are outright digs or provocations, it’s fairly understandable that we may turn them into idées fixes. And so Donald Trump obsesses over the length of his fingers, and so Tweety Bird tinks he taw a puddy tat. But often these slights are unintentional and more a question of perception. What’s going on here?

The Rev. Frank Desiderio, the chief adviser to the president of the Paulist Fathers, a Roman Catholic society for apostolic life, said: “Often this kind of comment is something people already believe about themselves. Whether or not it’s true, they secretly harbor this fear, so when you articulate it, it validates the fear.”

Father Desiderio said he was not immune to these kinds of comments’ sway. “As a preacher, whenever someone says after a Mass, ‘Oh, that was interesting,’ you know it’s not a compliment,” he said. “People are streaming out of the service and shaking hands and saying ‘Good homily, Father,’ but the one ‘That was interesting’ is what sticks with you.”

A second kind of unintentional swipe acts less like a laser or telescope than a fun-house mirror. Ms. Behary, who is the founder and director of the Cognitive Therapy Center of New Jersey, said that some unintentional swipes are powerful because they are “misrepresentations of who you are.” She explained, “If someone says, ‘Well, if that’s the kind of thing you like. …’ or ‘You liked that movie? Really?,’ it could mean to you, if it’s been said by a person who matters to you, that there’s something wrong with you, that you don’t have good taste.”

A third kind of statement casts a different spell. Barbara Hillary, an adventurer who, after reaching the South Pole in 2011 at age 79, became the first African-American woman on record to stand on both poles, said: “Often these comments have power because we are completely overwhelmed by their stupidity. They reinforce the idea that we are not born equally. And you’re made to feel guilty if you look at people and think, ‘I never seriously thought about sterilization until now.’” She added: “ One person I met put this wise, erudite expression on his face and asked, ‘What hotel did you stay at on the North Pole?’ That’ll stop you in your tracks.”

Two of the more common ways of dealing with the psychological pain caused by these comments are humor and counseling. In the first instance, the wounded party makes a joke of the incident by, say, deciding that the only person who would call you “sarcastic” is a person who gets his definition of irony from an Alanis Morissette song. Ms. Hillary said, “I try to amuse myself.” She told the person who asked her about the hotel on the North Pole: “I hung out by the pool a lot. I had a new bikini I wanted to try.”

In the counseling model, a therapist will typically encourage a patient to get over his wound or grudge by mentally revisiting the incident and injecting it with compassion. “You try to reframe the story by giving the benefit of the doubt to the offender,” said Father Desiderio, who leads workshops on forgiveness.

But for other people, holding on to the offense they took becomes a badge of identification or even honor. “I probably hold one or two grudges in my life,” Mr. Satyal said, not alluding to his brother. “But if I were to forgive these people, it would compromise my belief system. If I forgave them, a part of my integrity would die.”

Indeed, these perceived bombshells may even become a kind of rallying cry. Anna McCarthy, a cinema studies professor at New York University, said she had shared her own one with many other female academics.

“When I first finished chemo, and my hair was starting to grow back in the spring of 2012, I ran into a distinguished professor of film at a fund-raiser,” said Ms. McCarthy, who had had breast cancer but who had recently been found to be cancer-free. “When he expressed surprise at my short gray crop, I said, as I usually do, that I much prefer my hair the way it is now over the expensive blond tresses of my pre-chemo days. He told me that I no longer needed the long blond hair now that I was a tenured full professor.”