Good customer service is critical. People might not come back to your store if they're treated poorly by the employee at the cash register. Recently I noticed post-transaction meet-and-greets, if you will, at the top of receipts from Walgreens and Jewel-Osco, the latter a midwestern grocery/drugstore chain.
Michael's message is a little too eager. I don't know if he's going to get to first base with me the next time I'm at Walgreens. In other words, I won't buy an impulse item in the checkout line just because he's grateful he was allowed to serve me the last time I was there. Michael, I came into your store. I'm chasing you, so stop kissing my ass! Play hard to get next time and see if you get more repeat business. How about something like "I'm Michael. It was cool meeting you, I guess, but it's not like we're married now." Or "I'm Michael. Come back soon and I'll show you where I hide my stash." Or just "I'm Michael. Whatever."
The Jewel-Osco thank-you note is more subtle but also more direct. I'm intrigued, I'm confused, I'm blown away, and the words "thank you" are never used. Good job, Jewel employee.