To answer this more generally, instead of in example form people often have anxiety around social interactions particularly those they anticipate to be uncomfortable, conflict-ridden or dramatic. In a dating context (which is usually when this sort of thing happens, in my experience, but maybe you have something different in mind) it is usually a way to cease dating or flirting with someone without having to explain to them that you aren't interested. It avoids the tension involved in waiting for the person to react, the drama of any fallout and the awkwardness of spending any time interacting with them after you've dumped them.
While I understand that this is an effective strategy, I don't understand what makes people choose not to respond at all rather than just saying "I'm not interested."
A possibility I'm considering is that I have an abnormally large desire for explicit closure. This also fits with my enjoyment of (or at least lack of being bothered by) anvilicious political points and technical digressions in science fiction.
The other day, someone did something I didn't expect. It was something many people have done before; something that I thought of as very normal, but that I in no way understood and had not predicted.
As I said, this had happened many time before, so I wrote it off as "me not understanding people" or "people are weird" for a second, like I usually do, before realizing that "bad at" really means "lacking basic knowledge", which I had never realized before.
And then I thought "I should ask someone who is different from me why people do that, and eventually someone will have an answer."
But many people will have many more questions like this. So, what have you observed people doing time and time again, but never understood? Or something that you only understood after a long time or asking someone about it?
And can Less Wrong tell us, not necessarily why (I for one can make up evolutionary psychology fairy tales all day if I want) but what conscious thought process occurs behind these events?