There is an ancient Indian proverb that states “Be kind to unkind people. They need it the most.” Whoever penned that sentiment many centuries ago never met the guy in line behind me at the ATM. This guy is in a hurry — the kind of hurry where good manners go out the window and polite language is bypassed. I’ve been sitting here a total of 2.5 minutes, and this man is losing his mind. He’s gestured. He’s honked. He’s lowered the window and shouted something I cannot repeat here.

Apparently, there is an emergency of the highest level that requires he get his money out of this machine immediately.

What this lunatic doesn’t know is that his behavior has only caused me to fumble in my wallet, drop my debit card and forget my PIN number. And, if I’m honest, there is a devilish streak in me that is whispering in my ear, “If he’s going to be such a jerk, let’s make him wait just a bit longer than necessary.”

I shouldn’t listen to the devil in my ear, but today I’m just about to the end of my tolerance level. People have been ugly all day. Maybe it’s the weather. Maybe it’s the phase of the moon. Or maybe, just maybe, they’re all on a diet like I am and just need a piece of chocolate and a hot bath.

Nevertheless, the person behind me in line right now is just not getting any sympathy from me. Why should I be nice to someone so intent on creating a scene?

And then, as sometimes happens at the most unexpected of times, I can hear my sister’s voice. Her voice was so similar to my own in tone and inflection, but she always spoke so patiently. She was kind when kindness was not easy, and she made it seem effortless.

There’s a memory that is as clear today as it was 47 years ago. It stands at the center of my mind — a touchstone.

I was seven years old, and my grown-up sister had a new camera. It was polished black and silver, small enough to fit in the palm of your hand. On top was a cube that flashed when she took a picture. It fascinated me, those flashing lights and the clicking and whirring as the film advanced.

My sister, Carol, told me her new camera was not a toy, and while she loved taking pictures of me and my friends it was most definitely off limits. She trusted me to leave it alone.

But, oh that devil was already whispering in my ear even at seven years old. My hands itched to make the shutter click and the flash burst. “Go ahead,” whispered that devil, “no one will know.”

And so, with trembling hands, I picked up the camera and attempted to take what would now be called a selfie. The click was deafeningly loud, and the flash was blinding. I was startled into dropping the camera, and the flash cube broke. A thousand shattered pieces of spent flashbulb rained all over the floor.

I was horrified. “What have I done?” I asked myself. The devil on my shoulder was conspicuously silent. “Now you have nothing to say?” I hissed at him. But he was nowhere to be found.

Just then my sister walked around the corner. It took only a couple of seconds to take in the scene and realize what I’d done. I braced myself for the fury she must surely have been feeling. Or, even worse, that look of extreme disappointment that is far worse than anger.

But my sweet sister, who was ever patient and kind, knelt down and picked up the camera. “I should have taught you how to use this camera. You’re smart enough to be able to do it yourself.” And she taught me all about the shutter and the flash cube (she had a spare one in her purse) and how to load the film.

She let me take what we now call a selfie. It was goofy and out of focus, but I had so much fun.

And then we had a photo shoot — myself and every one of my stuffed animals, all dressed to the nines.

There is a picture in my box by the bed. In it, I am seven. My face is flushed, and my eyes are bright. I am clutching a bright pink stuffed cat around the neck. And I am as loved as I ever was in my whole life. I had been forgiven. I’d been shown mercy and kindness even when I did not deserve it.

And so, now I have completed my transaction at the ATM, and it is time to show mercy and kindness. Even to the jerk behind me in line.

I lower my window and wave back at him. “I’m sorry it took so long. I appreciate you being so nice. Have a wonderful day!” I say with genuine kindness in my voice.

I have no idea if he thought I was being sarcastic or if he even heard me at all. But it doesn’t matter. Ralph Waldo Emerson said, “You can never do kindness too soon, for you never know how soon it will be too late.” Ralph said it, but my sister taught me that. She is still teaching me so many things.