All I wanted was a slice of pizza, but as I stood at the counter wondering if I should also get a mocha smoothie, a frizzy-haired woman wedged her way in front of me.

“;You forgot my churro!”; she blurted at the woman behind the register.

“;You didn't order a churro,”; barked back the cashier.

I jumped a little.

“;Yes, I did. My daughter asked for it.”;

The cashier rolled her eyes. “;You did NOT order a churro,”; she snapped, though moving to the churro station.

Frizzy turned to look at me, her voice now quiet. “;She's having a bad day,”; she said, nodding her head toward the register.

I indulged her with a weak smile, not wanting to appear entirely sympathetic lest the cashier turn her anger on me. Her fist—with a paper-wrapped churro—emerged through the takeout window.

“;Take your churro.”;

“;I DID order that churro.”;

“;Whatever. Enjoy.”;

Frizzy snatched the treat and hurried away.

It was then my turn, and I had apparently done the cashier a disservice by showing up. She snarled when I ordered a soda with my cheese slice. My lunch was unpleasant, and not because of the grease puddles on my pizza. It's depressing when people are cruel. Why are we so nasty?

We live in a culture of mean. We love television shows and movies in which people attack one another over stupid things like tacky clothes or bad hair or being a Republican. We yell at waiters who mess up our orders. We laugh at the girl whose tummy spills over the waist of her jeans.

We scream obscenities at the jerk who cut us off on the freeway. And we happily hurl insults from behind screen names online.

Where does this meanness come from?

People who are mean have probably been hurt in some way. By a cheating girlfriend. By a bad review from the boss. They see themselves as victims and respond by building walls to shield themselves from more harm.

So how should we respond?

It's tempting to hurl back our own version of clever cruelty. I know someone pumped with clever verbal attacks against those who steal parking stalls, for instance. But is that the best solution?

I subscribe to the theory—however naive it might be—that we can improve the world by stopping cycles of mean and dishing out kindness.

I'm not saying we should be sunshine and smiles 24/7. That's just scary.

And I get that people have bigger troubles than flat tires and coffee spilled on a new white shirt.

But to me, good will is like recycling: A little bit can make a difference.

So even if you've been wronged, save a stranger's day by passing on kindness instead of anger. Thank your bus driver. Tell that quiet geek in your English class that you think her writing is smokin'.

After all, a churro might cost a dollar, but being nice is free.