The conversational short-circuit

I don't mean to imply by the following story that I usually know what to say. I have anxiety in social situations (not of the same nature as the condition known as Social Anxiety Disorder) and I tend to be shy. But in familiar contexts, surroundings, and situations, where I have over time constructed a decent model of what is usually expected of me, I can rely on shortcuts, and at work, with my friendly work acquaintances who are usually speaking to me in Finnish, I tend to quickly, even automatically reply with "Mmm!" or "Hmmm?" or "Mm-hm" when something else doesn't leap to mind, as it often doesn't due to factors like not understanding what they said or not knowing what they're referring to.

But last week my friend Ella was relating something about a sick grandmother being sicker recently and I got so distracted thinking about what she said - like just basically processing it and then continuing that with stuff like mental math for how old she'd've been and stuff - that I hadn't even got around to wondering how I was supposed to react and I suddenly realized way too much time had passed, during which my face was no doubt completely blank due to my thoughts being focused inward. Ella was late and ran back to the cash register, and she wasn't offended or anything, but I was actually startled out of my thoughts and a little alarmed to realize I had lost track of what exactly was going on around me (couldn't remember what facial expressions people were making and wasn't quite sure how long I'd inadvertently been silent). I was focused so far inward that I was too slow to decide what intonation of "Mm" noise would have been appropriate until it was too late!

And I realized that while my mother was dealing with the deaths of her grandparents into her 50s - all of whom were terrible people who were physically and/or emotionally abusive, ( cut for some more discussion of abusive parenting, though nothing graphic )