One awesome customer service experience can keep you flying all day. One lousy experience can ruin your whole week.

So here's to the cashier at our local supermarket in St. Louis. You know who you are, buddy.

• As I approached your checkout lane, you looked at me as if I had just shot your dog.
When I said “Good morning,” you stared at me icily, then joylessly rang up my purchases.
When I asked you a question about the card reader, you looked straight at me and actually said … nothing.
As I waited for you to bag my items, you gave me a glance that said, “You, personally, are the reason why my life sucks. I hope you die.”
Then you wordlessly threw my stuff in a bag and mentally kicked my butt out the door.

And you know what? Your little misery fest actually worked. For a while there, I felt awful. I let you crawl completely under my skin. Believe me, it wasn't a pleasant experience, having someone as entirely pathetic and miserable as you under my skin.

Finally, for the sake of my own sanity, I told myself you were just having a bad day. No one can be that awful, that mean-spirited, that completely rotten all of the time.

So really, I'm sorry for the angst you felt that day, and I apologize for the inconvenience I caused you. It couldn't have been easy, having to deal with an actual human in your state.

If you don't mind, though, can I offer a word of advice? Don't let your employer see that act. They tend to frown on customer-facing personnel treating actual customers like crap.

Come on, people — at least pretend to care. Do that and I might shop at your store again.

Put forth a little extra effort and treat me like I mean something to you, and I'll be a customer for life.

Treat me like Cashier Crabbypants, though, and you run the very real risk that I'll never set foot in your store again.

Are your people treating your customers like royalty? Or like an inconvenience?

In a world where social media and instant communication are the norm, what does the answer mean for your company?