Not every customer is hearts and roses. Getty Images

Absurdly Driven looks at the world of business with a skeptical eye and a firmly rooted tongue in cheek.

You've seen them at Starbucks, I'm sure.

They don't know what they want. They think the barista should know what they want.

Or they come in with an attitude and speak with a tone that would even offend Donald Trump.

What can you do?

A certain proportion of humanity is rude.

My own entirely non-scientific research suggests that it's around 40 percent and rising.

A business owner has to just deal with it. Or throw them out, of course.

But then there's Marisel Valencia Madrid.

She doesn't want to get into a fight with customers. She had a far better, beautifully businesslike idea.

She charges them more.

If you go into her Restaurant Blau Grifeu and throw your weight around, offer excessive self-importance or generally behave like an annoying twerp, she charges you more for your coffee.

Conversely, if you're polite, sweet and behave in a civilized manner, she charges you 40 percent or more less. If you can keep up with my peculiar construction there.

Madrid is from Colombia.

Which is another peculiar sentence.

Just to complicate things, Madrid's restaurant is in Spain. In Llançà, near Girona, to be precise.

She told the London Times that she was surprised how rude Spaniards can be these days.

"People seem to be in a rush these days and forgetting to say 'please' when they ask for something," she said.

So her menu has a very simple rubric:

Un café 5 Euros

Un café, por favor 3 Euros.

Buenos Días, Un Café Por Favor 1.30 Euros.

Madrid isn't even the first to try this highly sensible maneuver.

The Petite Syrah Café in Nice, France started it as something of a joke.

Owner Fabrice Pepino told the Local: "At lunchtime people would come in very stressed and were sometimes rude to us when they ordered a coffee."

It's hard to know whether stress is destroying us even more quickly than technology.

Perhaps the latter contributes to the former in a circle that is virtual, but not virtuous.

We're constantly being pursued by something, as much as we're constantly pursuing something.

As our friends become as virtual as our memories of calm, considered relaxation, we're becoming awful people who think the online, on-demand economy allows us an economy of words, gestures and even basic courtesies.

In my local Starbucks, those basic courtesies are still observed by many.

There's a certain unspoken agreement that life is an unfair fight that we're bound to lose.

So customers tend to be pleasant, if occasionally unsure of where they actually are.

Perhaps, though, Starbucks -- whose CEO Howard Schultz is known for his social and political activism -- might experiment with the Pepino-Madrid Convention.

I've been to many a New York Starbucks, for example, where the staff are a lot more pleasant than the customers.

What a delight it would be to suddenly slap what is, in effect, a rudeness tax on their lattes.

My suggestions are as follows:

Ordering coffee while you're talking on your phone: $9

Ordering coffee while you're texting or looking at Instagram: $8

Ordering coffee without saying 'please' or 'thank you': $8.

Ordering coffee while talking on your phone and not saying 'please' or 'thank you': $25.