halloween at Vons

This morning, as I do on most Monday mornings, I had to run those last minute errands. I usually hate grocery shopping. Once upon a time it was fun, a trip off campus to the Big Y to get lots of delicous things to make. Now, in the frugality of living alone, shopping trips are tedious. I go to Henry's for produce because they have fresh locally grown fruits and vegetables, but they don't have things like a pasta selection or a meat department that can cut things for you. So, in order to get what I want, I have to make trips to several different stores. Vons, like Big Y or Stop n' Shop, is a huge chain where one can get things like giant cans of broth or packets of oatmeal. North Park produce has the ethinc specialites that I want, including reasonably priced teas, olives and cheeses.
So here I am picking up the canned/dry goods this morning at Vons. I had signed up for a Vons card to save a few dollars, realizing only afterwards that I had at the same time signed away my access to my food intake habits. I imagine that in this case an insurance company says to me at some point in the future, 'you never eat fruits or vegetables, you have a diet high in dairy products.'
Ahead of me in line was a mother and three elementary school girls. The cashier, taking the training of perky and eye contact too seriously for my taste, asked the grils what they would be for Halloween. The oldest gril answered him solemnly that they didn't celebrate Halloween. He leaned in and told her that he didn't either. Then looking up at her mother said that he used to celebrate Halloween then he realized what is was all about, and nodded passing something between them that I didn't quite understand. He ended by thanking her, reading her name aloud from her receipt, and making eye contact again.

Two things about this witnessed exchange:

It always bothers me to have cashiers say my name. Just as when I worked for the Christmas season at Crate and Barrel, I winced at the thought of customers who didn't know me using my name. In that case, I used a fake nametag, and was Rose for two months. Why do we have to pretend that we know each other when we buy things? I don't want anyone using my name, reading it from a receipt, to make me feel that I am in a welcoming friendly environment. He thanked me, Mrs. Taranto(eye contact made), and I went on my way. At least the bag boy, who was wearing a costume, looked up at me when I asked him about his face piant and the eye contact made was genuine and not rehearsed or dictated by management.

And what was he talking about? What historical origins would make someone, aside from religious conversion, stop celebrating Halloween? Was this something to say to 'relate' to the customer? Or is he in possession of some terrifying knowledge that all parents with children should be made aware of?