I’ve been asking myself that (why I find such seemingly innocuous interactions annoying). I don’t have trouble with the so-called blather aspect of it.
I don’t mind chit-chat. I think when it’s about my food selections, it seems more personal and is therefore crossing (what only I perceive as) some sort of boundary of propriety/etiquette. You don’t ask me about what I eat, total stranger, and I won’t ask you about your sex practices. What if I’m bulimic (I’m not, but what if I were)? What if I’ve been food-shamed, or fat-shamed, during my childhood? Now I have to be triggered and/or discuss this with you?
To use example #1, to the cashier who asked “Are you having a party?”, I would either have to lie and say, “Yes, I’m having a party,” or confess “I am going to eat all of these potato chips by myself”–a fact which I did not feel like sharing.
So when she asked, “Are you having a party?”, I replied with a joke: “Yes, party of one, over the course of many weeks.” She laughed and said, “I love it!” Well, from the outside, that looked like a fun, casual social interaction–but on the inside, I felt a twinge of embarrassment and also, annoyance that I was made to discuss this when I didn’t really want to–unless I wanted to reply rudely (which I did not) or go into why I didn’t want to talk about it (which I also did not want to do). I just wanted to pay for my food, not talk about it! If we must talk, let’s talk about the weather, or that it’s another darned Monday, or golly gee, too bad our team lost yesterday, but we’ll get 'em next time, now that Kowalski’s ankle is healing!
On the other hand, on a different occasion, when I was buying a loaf of bread, another customer asked me “Is that good bread?” I replied, “Yes, it’s excellent bread!”–an interaction which I didn’t mind at all, because he was asking me about the brand/type of bread, and NOT my personal eating habits. So I didn’t take it personally. On the other hand, if he had asked, “Are you going to make ten sandwiches with that? How long does that usually last for you?”, he MIGHT be asking that because he wants to know how long a loaf would last for HIM…or he MIGHT be hinting that I’m some kind of glutton and/or a fat f*ck.
In example #3, when the skinny woman was eyeing my ice cream, she MIGHT have been envying that I could eat ice cream because she has denied herself that treat…OR, the little smirk on her face may have been less vicarious and more vindictive: “Ah-HA! I CAUGHT you buying ice cream, you sinful thing, and I’m gonna make sure everyone in this store knows it, by announcing it as loudly as possible!”
So, yes, it’s entirely possible that I’m simply reading into it (hence the purpose of this post, to get feedback). But it could also be that some people are actually being judgmental–whether they’re aware of it (and being intentionally rude) or not (and are merely oblivious).