For 40 years, I kept this reproach by a customer in mind.
The incident happened when I was on a moving stall at a hypermarket.
We were very busy that day. Items sold so fast that I could barely replenish the supply. I had to go back and forth between the stall and the truck. There was no time to make a pretty display, so I just cut the lids out of the carton boxes and left them to be sold. Desperate, I prioritized replenishing the supply over customers.

It was inevitable that I would bump into a customer. The space we rented was limited, and the alleyway was narrow even for one person, and I was carrying boxes.
Usually I would call out, “Excuse me, let me through.” But on that day, I didn’t. The customer I bumped into scolded me mercilessly.

The customer had every reason to be angry. My mind was occupied with replenishing the merchandise, and there was no room left for customers. I was so absorbed that I didn’t notice I had bumped into someone or say, “Excuse me.” I was wrong. That reproach was a trigger reminding me of the importance of doing your assignments, but the customers should always come first. Never forget that. That was the lesson I learned that day.