I was on a Southwest flight the other day, and we were about a half-hour from our destination when one of the flight attendants got on the PA to announce there was someone on the plane with a very special birthday. Her name was Miri and she was turning two. Because the majority of Southwest flight attendants seem like they wish their true career was performing on Broadway, this one asked everyone to sing “Happy Birthday” along with him.

More than half the passengers did, but since I prefer not to expose the public to my very sub-par singing voice, I didn’t join in. But at the end I clapped for the kid — as did nearly everyone on the plane.

One of the people who didn’t applaud was the guy next to me, who had not said a word the entire flight — not even a “hello” when he sat down. Yet this is when he spoke up, asking me in an annoyed tone, “Why are you doing that? Do you know the kid?” I replied that I didn’t, nor did I know which row she was sitting in, but it didn’t matter — because being nice costs me nothing.

Look, I understand that people have bad days, or their lives aren’t going the way they’d like. I also know that social media has made a not-insignificant portion of our population preternaturally grumpy and angry, believing they not only have the right, but an obligation, to express their irritation for all to hear.

Whatever his issues were, he continued, “The kid is two. Do you think she’ll remember this in ten years?” I couldn’t believe what I was hearing, so I played right back at him: “No, she won’t. Will you? Is that your only criterion for being polite?”

At this point, he’d had enough of me, so he grunted dismissively, put his headphones back on, and waved me away.

I had one more question for him, but I only asked it inside my head: “Can you remember your last happy day?”