In busy retail stores with complex systems, even the smallest error can cause big problems.

One cashier’s single mis-click led to a jaw-dropping total and an unexpectedly patient customer.

Read on for the full story!

I made a mistake while ringing a customer up.

I work at a pet store, etc. etc.

One day I was ringing up a customer. We have loyalty cards, so I typically enter their phone number into the customer field, then arrow down to the sale section and ring her items.

The cashier explains where they went wrong.

I had been pricing before this woman showed up, which meant I was in the field I ring items up in.

(We had a sale going on this particular item, so I was using this instead of the price lookup, because price lookup applied the sale discount to the item.)

This woman showed up with a cart full of items. I asked if she had a card with us and she said no, so I arrowed down and started ringing her up.

The first item didn’t go through, so I clicked on the field again and scanned again. Bingo.

At the end of it all, she had about 20 items.

But upon further inspection, the total didn’t look right at all.

“Okay ma’am, your total isssss… just under $3 billion dollars? Hold on.”

Turns out, that first item I scanned was scanned into the tax field. So it applied the UPC and treated it as a dollar amount.

When that happens, the only way to fix it is to start over and ring everything up again.

The customer reacted way better than expected.

She had a lot of cans and toys, so it took a while, but she was very kind about it and even signed up for a loyalty card after.

Messing up is always terrifying, but it is truly refreshing when someone responds with kindness instead of impatience and anger.

It’s okay to make mistakes, and this kind customer reminded this stressed cashier of that important fact.

What did Reddit have to say?

Some mistakes are so outlandish that you just have to laugh.

Small mistakes can make a big impact.

The cash register can be a scary place.

Some mishaps get caught just in time.

This situation could have ended very poorly, but the customer’s kindness made all the difference.

Moments like these remind retail workers that not every mistake leads to disaster.

If you liked that story, read this one about grandparents who set up a college fund for their grandkid because his parents won’t, but then his parents want to use the money to cover sibling’s medical expenses.