Someday last week, somewhere in the mid-Hudson Valley, I had a bizarre exchange with a total stranger. This happens to me on occasion. You’d think, by now, I’d be used to it.

But this last time was different.  This last time haunted me: the woman, her meltdown, the two young men in the shop with us that day.

She was somehow so vulnerable in the extremis of her pain, somehow so broken in her rage. The fellow who accompanied her called her by name in his efforts to calm her, but I won’t repeat it here. I won’t identify the sandwich shop where the incident took place, and I won’t specify the locale. It happened. It truly happened. Let’s leave it at that.

It happened when I walked in to buy two subs. The shop was empty except for one employee, a young man with brown skin, a gentle manner and a light accent of Middle Eastern or South Asian origin. I gave him my order: Two sandwiches, please. Turkey, bacon, lettuce, Swiss cheese, tomatoes, red peppers, ranch.

As he assembled them, the young woman in question entered with her companion. The employee spoke with them, took their order, then turned back to me to finish and ring me up.

“I’m really thirsty,” the young woman declared with sudden urgency. “Can I have a cup?”

He looked up. “I’m sorry?”

“A cup,” she said. “A cup. A cup.”

“A cup? What kind of a — ”

“A CUP,” she repeated. “A CUP? Do you know what A CUP is? Have you never heard of A CUP?”

Saying nothing, he reached for a large paper soda cup.

“Are you the only person working here today? Is anyone else here?”

Still saying nothing, he handed her the cup. This failed to placate her. She started shouting.

“I said, IS ANYONE ELSE WORKING HERE TODAY, OR IS IT JUST YOU? Are you alone here? Are you IT? Is NO ONE ELSE HERE?”

That’s when I said: Hey. Hey. Give the guy a break. He just didn’t know what kind of cup you wanted.

Startled to hear from an outsider, she shot me a glance filled with acid.

She said: Mind your own business!

I said: If you’re rude to someone in front of me, it is my business. This is a public place. The guy just works here. Leave him alone.

She said: You’re not my mother! My mother is dead! Mind your own business!

What I should have said: I’m sorry your mother is gone, but you still have no right to treat this guy badly.

What I actually said: I have a dead mother, too. And my dead mother taught me to speak up when I hear someone being treated with disrespect.

Immediately I recognized this as a mistake. I should not have countered her Dead Mother with my Dead Mother, as Dead Mothers, once invoked, have a way of ramping up any conversation. And it did indeed ramp up. The young woman went completely ballistic, flailing her arms, shouting, spewing F-word upon F-word upon F-word while I howled CALM DOWN CALM DOWN CALM DOWN and made repeated “time-out” gestures like some ineffectual and somewhat desperate hockey referee.

I thought: Shit! What did I do?! She’s totally lost it!

I thought: Shit! How can I stop this?!

Then I thought: Shit! What IS it with me and total strangers!?!

Meanwhile, the young man with her —  friend, boyfriend or brother, I have no idea — looked pained and exhausted, as though he’d been through this way too many times before. He spoke her name tenderly, knowingly, urging her to leave. “Let’s go. Come on, let’s go, let’s go,” he said, and I felt an instant flood of sympathy.

But she kept at it. More flailing and shouting. More F-words.  I don’t recall the exact substance of her complaints, but the gist of it was unhinged, toxic outrage at being judged — by the world, by anyone, by me. I had no right. How dare I. She didn’t need this. Who was I to say. Et cetera.

Only when she slammed the paper soda cup onto the floor did I realize it was filled with ice. For a split second, the four of us — we two ladies, the employee, the friend — paused and stared as the scattered cubes shushed across the floor. Then the young fellow took the woman by the arm, uttered one more urgent “come on,” and they were gone.

That’s when another woman entered the store. “What happened?,” she asked, picking up the cup. We told her. She asked if I was all right. Yes, I said, and we all looked down at my shaking hands.

“Do you want me to call the police?” asked the employee.

No, I said.

“Are you sure?”

Yes, I said. I thought: That would ruin her day and maybe her life. And she didn’t hurt me. She didn’t even touch me. She only swore and fell apart.

I regarded the young sandwich-builder before me. He was utterly poised, calm and quiet. Not a peep from him throughout the whole ordeal. Not a flash of anger.

I said: I’m so sorry. I’m so sorry.

I said: I didn’t mean to create such a scene — to do this to you in your workplace. I only meant to tell her she shouldn’t be rude to you.

Again I said: I’m so sorry.

He shook his head. “I work here, so I couldn’t really say anything. It’s my job,” he said, and I felt an instant flood of sympathy for him, too. I wondered how often customers were rude to him for indiscernible reasons, and how often he stifled the urge to talk back.

Then he shot me a look of quiet bafflement and sorrow. “Some people,” he said, shaking his head once more. “Some people just don’t respect their elders.”

At that I almost burst out laughing. The kid was talking about me. I was an elder. Of course! The white-haired lady assailed with F-bombs by the obstreperous youngster!  In his country and culture of origin, such a scene would be unthinkable and appalling — far worse than the woman’s rudeness to him was her rudeness to me, at least in this young man’s view.

I wanted to hug him. Instead I asked his name. I said thank you, goodbye and God bless you. And I left with my turkey sandwiches.

Afterward, I replayed the episode over and over in my mind. I wondered what had motivated the woman’s short fuse and incivility. Was it the man’s race? His (presumed) religion or immigration status? Maybe. But maybe not. Maybe he was just in the wrong place at the wrong time, and maybe I was, too. Maybe this woman had had an absolutely, positively shitty day. Maybe she’d been fired from her job, ditched by her boyfriend or — who knows —  ripped to a million little pieces by a total stranger in public. Maybe her mother had, in fact, just died.

I don’t know. But I know she isn’t having an easy time of things, whoever she is, and I also know her name. I know the sandwich man’s name. In a strange way I can’t quite understand, much less explain, I feel a bond with them both, having shared a moment of plain, painful, unfiltered humanity that was stripped of all protective layers. In that one volatile moment, we were naked together. Defenseless. And in our defenselessness lay an odd sort of intimacy.

Sometimes I think this is the challenge and calling of life: to witness each other at our worst, and to do our best regardless.

So I feel close to those people that day. I always will.  Once total strangers, they’re known to me now.  They mean something. They matter. I can’t shake them off, I don’t expect to shake them off, and I won’t try.

But I am never, ever, ever setting foot in that sandwich shop again.