I will happily stop and chat with you if you demonstrate that it is worth the time and interruption (if I was lost in thought, that will take at least 5-10 minutes to get back to).
If not, I will not let you know. I will just fume, blame and judge you for some time after.
"Hey sorry, I've got some things on my mind right now and can't really talk. Have a nice day though".
That takes less than 10 seconds to say, let's you protect your time and peace of mind, and as a bonus there's no need for fuming, blaming, and judging that the other person won't ever even know about.
The people likely to talk to strangers unprompted are also likely to ignore those kind of messages. Anything that can lead to further conversation can be used (like "oh, what's worrying you?") so actually politely nodding and smiling without giving any footing to further conversation works better than being assertive.
> The people likely to talk to strangers unprompted are also likely to ignore those kind of messages.
No, that obviously false. They might be more likely, but they are certainly not likely.
I don’t think it’s false, much less obviously false. On one hand I have my personal experience about it, on the other you can see there’s only a small range in the “I want a conversation” scale where they want it enough to ignore the nonverbal signs that the person doesn’t want to talk but not enough to ignore the verbal ones.
This requires social skills many HN users are lacking.
>let's you protect your time and peace of mind
Not even close.
> If not, I will not let you know.
This is 100% completely on you, then. If you don't inform people you're being interrupted or that what they are doing is bothering you, they have no data to telling them to stop, and any energy you spend on silently judging them or being frustrated is only harming yourself.
No, it's on you. You can stop before you even begin by simply not interrupt and bother people for no reason. You're creating a problem and then blame me for not stopping it.