Many years ago, when I was about 19, I took a job as a bagger at a grocery store for the summer. It was a job my father lined up for me and insisted I take, not having any other prospects at that moment. I lasted one day and quit when I found out it paid $2.40/hr. Minimum wage, before union dues came out.
In just that day I remember while on break a girl and boy who worked there, both about 17, telling me about some of the little games they played to entertain themselves. One was to call for a price check EVERY time someone bought a tube of Preparation H, passing it down through the line of customers to the stock boy that would wait at the end. They had some code when they were calling for the price check.
At the time I thought to myself, "how childish!"
A few years later I was grocery shopping at that store. I recognized the cashier as that girl, but noticed that she didn't remember me. It didn't dawn on me that I had a tube of Preparation H in my cart until I watched her purposely cover the UPC symbol and fumble with the scanner. With a smirk, she promptly called for a price check, passing the tube down the line of perhaps five other shoppers.
As I paid for my purchase I looked her straight in the eye and said loud enough for everyone in line to hear, "Honey, you didn't embarrass me at all with your little prank, but you did irritate me by wasting my time and the time of everyone else in line as you played it."
She turned beet red and I left quietly with my groceries, leaving her to wait on the five informed customers behind me.
I didn't care to tell a manager about it. I figured she might have learned a lesson well enough. She did work at that store for a few more years and waited on me matter-of-factly after that. I thought of purposely going through her line with nothing but a tube of Prep H and a smile, but I never did. I kind of wish I would have.