Like a zombie, I shuffled across the Philadelphia airport. It was 5:30 am, and I hadn’t gotten much sleep on my red-eye from Seattle. This cross-country trip required three flights, instead of two, and each plane change was stressful.

A cafe caught my eye, and I joined the line to buy some juice, setting my luggage down and shuffling it forward each time the line moved.

I hardly noticed the older woman in line behind me, until her husband joined her. “I don’t know what you were thinking, you $@#%! You should have $@#^@!” she said to him, her tone loud and acerbic. He responded defensively, then started making nasty accusations at her. I thought about giving up my place in line to get away.

It devolved into one of those toxic “You always!” and “You never!” arguments that’s impossible to resolve. Fortunately for me, they disagreed vehemently about the cafe and went somewhere else.

I felt icky, contaminated by their toxic emotions, but also relieved. It gave me a chance to appreciate that my life is not like that.

By most measures, my morning went downhill further from there. Bad weather delayed my second flight, and when I arrived in Charlotte, my flight home had been cancelled.

Luckily, I didn’t have the same attitude as the angry couple I’d overheard earlier. I took a deep breath and walked to the customer service counter, where a smiling customer is an anomaly. I decided to be the anomaly.

The customer service agent worked out a couple of options and printed new boarding passes. As she handed them to me, the agent still looked concerned. “I need your luggage tags,” she said. I was befuddled by the request, then I realized why she was frowning.

“I only have carry-on luggage,” I said. Her face lit up with a huge smile. “Wow! You’re good to go, then!”

I had plenty of time to catch my new flight to Orlando. With a sigh of relief, I headed for the nearest bathroom.

It was sparkling clean, and just inside the entrance was a display with free candy, hand lotion, hair products, and feminine supplies. The clue to this largesse was the accompanying tip jar. I had just entered the domain of one of the Charlotte airport’s restroom attendants.

This woman, though, was no mere attendant. She was earning her tips as a Bathroom Ambassador.

She bustled around the large bathroom with a cleaning towel, wiping the counters as she greeted women with a cheery hello and a smile. “Hi, how are you today?” She also served as a traffic cop, keeping track of which stalls were in use. “Come on over here, I’ve got a great room for you, lady!” “Here, take this big one — you’ve got a lot of luggage.”

She made the bathroom so pleasant, I wished they had more comfortable, less-specialized seats in there. I would have stayed for a while. She came over and said hi as I was washing my hands. “If you’re going someplace sunny, take me with you!” she quipped.

“I don’t know,” I said, rummaging around for something to put in the tip jar. “You’re making it pretty sunny in here!”

I had over an hour to kill, so I stopped at a Starbucks for a cup of tea. I didn’t even have to use money for this treat — I paid for it with a gift card my brother Hank had given me.

Every time I use this gift card, it makes me feel good. It’s as if he’s giving me a Christmas present over and over.

After my Philadelphia cafe experience, I found myself looking curiously behind me, to see who was next in line. It was a woman about my age, black, with a southern accent. She was alone and had no luggage, perhaps an employee from one of the other shops. She placed an order very similar to mine, and as she fumbled in her purse for the money, I had a brainstorm.

I handed the gift card back to the cashier. “Here, charge it to my card,” I said. The cashier didn’t miss a beat, just swiped the card and handed me a new receipt. She probably assumed we knew each other.

The woman in line behind me went through a series of reactions. There was initially confusion as the cashier refused her payment, and then astonishment that a stranger would pay for her order. Apprehension — was I going to ask something of her? And finally, she got it, and was simply grateful. She’d never experienced anything like this before.

“This is one of those pay it forward things, isn’t it? Now I have to do something nice for someone else?” she said. I just smiled and said, gently, “Only if you want to.” I slipped away to put some milk in my tea, and she followed me across the restaurant. “Thank you! You really made my day! What’s your name?” If I hadn’t been carrying a very full cup of tea and two pieces of heavy luggage, I suspect she might have hugged me.

Despite my lack of sleep and change of plans, I was on Cloud Nine for the rest of the day. If I hadn’t jotted a note about the angry couple in Philadelphia, I would have forgotten about them completely.

For many people, the experience of traveling by plane is miserable. The security process takes away all privacy and dignity. When you reassemble your belongings and put your shoes back on, you no longer have your autonomy or your freedom. Your fate is in someone else’s hands.

Your fate, perhaps, but not your experience. Each of us can choose whether to be miserable or not. The couple in the cafe line? They chose to be angry. Me, I choose to smile, and to do things to help other people smile.

Sometimes, like when my flight gets cancelled, I don’t feel like smiling, but I paste on a smile anyway. Eventually, someone sees my smile and smiles back at me. Then the game is up — I can’t help it, I’m smiling for real now! The next thing I know, I’m smiling at everybody, basking in the cheerful smiles I get in return.

Meps, smiling at you: (=