I arrived toward the end of your encounter when your face was already red with anger - when the poor employee you were screaming at looked like she wanted nothing more than to scream at you. Instead, she addressed you as "sir" and tried to explain the situation to you calmly one last time. You left in a huff, muttering under your breath.

To be fair to you, I did not see how the situation began, nor do I know what you've gone through - but I did see the aftermath.

For the ten minutes after your departure that I stood in line, I saw the impact your interaction left on the employee. I watched her heatedly repeat the story to not one, but two, of her co-workers, telling them how terribly you had treated her. I listened to her explain to them how she had gone out of her way to assist you, had done more than she was required to do to aid you, and was not given so much as a thank you in return.

She remained upset far after you were gone, her day ruined before nine in the morning.

To you, the day went on, likely soured in the same way hers was, the only difference is that you did it to yourself.

It's not just you, though - it's all of us. We wander through life unaware, surrounded by thousands of other lives that don't matter to us. You'll never see that employee again, will never know the impact you had on her. What does it matter to you, really, if she had a bad day? How does it affect you?

Likely, you will forget that the encounter ever happened, and maybe she will too. But maybe she'll remember that moment for much longer; maybe she'll always remember you as the man who screamed at her for trying to help.

Anyone who has ever worked in customer service will tell you that it is no easy feat. There's is nothing, after all, more unpredictable than other people. But for every person that yells at you, there is one that smiles. For every person that ruins your day, there is one that makes it.

We don't choose who we encounter in life, but we choose how we impact them. We choose whether to be the man that screams until their face is red or the man who puts aside their bad day to smile at another. Our choices are what define us - even the choices we will soon forget. Every little moment makes us who we are.

We will never know the impact of ourselves on the life of another, but that does not mean it won't affect us.