When I went grocery shopping this morning, I was close to a mom pushing a cart with her little boy in the seat. I would guess he was about two or three years old. As they do in the grocery store, some one made an announcement over the PA. You know: "so and so please report to the frozen food aisle" or something like that.
At the end of he announcement the person added a perfunctory "thank you ". Just as I passed the mom with the little boy, I heard him yell "You're welcome!"