The Self-Checkout Incident and the Fear of Not Knowing

Today, something slightly strange happened at a convenience store.

There were about three people lined up in front of the register.

I looked around the register area and noticed an empty self-checkout machine.

There did not seem to be any particular restriction on using it, so I went straight to the self-checkout.

Note: In Japan, you generally need to use a staffed register when buying alcohol or cigarettes, or when paying utility bills.

Then I heard a voice from behind me.

“Please line up properly.”

Apparently, a man waiting in line thought I had cut in.

For a moment, I could not understand what was happening.

The self-checkout was open.

No one was using it.

So I used it.

That was all.

We Were Looking at Different Worlds

Thinking about it later, I do not think this was a case of someone being clearly at fault.

From the man’s point of view, it probably looked like this:

“Everyone else is waiting in line, but one person is breaking the rules.”

From my point of view, it was simply this:

“I used an available machine.”

We had different information.

So we were seeing different worlds.

To be fair, I have had a similar experience myself in the past. I once spent a long time waiting beside a lane that turned out to be reserved for customers with reservations.

At first, I was quite irritated watching people enter without lining up in the same lane. I eventually understood after a staff member explained it to me, but still.

Looking back now, the man today may have been feeling something similar.

I Ran Away

Of course, I could have explained.

“This is the self-checkout.”

That would have been enough.

But from experience, I know that throwing the correct answer at someone in that kind of moment rarely leads anywhere good.

I avoided eye contact, finished paying, and left.

Avoiding trouble mattered more than proving whether I was right.

When I was younger, I might have argued.

But not anymore.

Life is finite.

If I have time to explain how self-checkout works, I would rather go home and drink a cola.

Round Two

But the story did not end there.

Just before I left the store, the same man was now complaining to the clerk at the staffed register.

“Then you should explain it.”

Apparently, his anger had shifted from me to the clerk.

I felt sorry for the clerk. How could the clerk know what that man was going to buy?

The self-checkout had been there from the beginning. The man could have gone there from the beginning.

It was not hidden.

But from his perspective, the feeling probably remained:

“I was the only one who lost out.”

Lack of Information Makes People Angry

This incident reminded me of something.

Of course, people get angry when something bad is done to them.

But maybe people get just as angry when they feel they lost something simply because they did not know.

And that anger does not always go toward the actual cause.

It went toward me, then toward the clerk, and perhaps after he got home it went toward someone else.

Meanwhile, all I had done was finish paying about one minute earlier at the self-checkout.

Closing

From an engineer’s point of view, the root cause of this incident is clear.

The cause was not the self-checkout.

It was not the man.

It was not the clerk.

It was insufficient requirements definition.

The missing message was:

“Customers buying regular items may use the self-checkout.”

That said, requirements definition in human society is usually incomplete.

So the probability of this incident recurring is extremely high.