I was just sitting at the mall taking a break from mall walking. A man walked over to me when I wasn’t even looking up. He said "I haven’t seen you here before. " I said I wasn’t really here to talk to people and got up and walked away. He said he would leave, he may even have said sorry. I said I was ready to leave anyway. In retrospect I think he may have just been slightly mentally challenged so I wish I had been a little softer, he did not turn out to be aggressive. Looking for suggestions on something still clear and firm but more polite? This scared me for some reason, I think how fast he walked up and sat down near me.
Editing to add a key detail, he sat down close to me which is probably what made me more nervous than I would have otherwise been. I appreciate all the thoughtful feedback I’ve gotten and interesting discussion.


Maybe it’s a cultural thing? Apparently America is unusually friendly compared to the rest of the world, and striking up conversations with strangers is pretty normal.
Yeah, I’ve met Americans who somehow manage to do that. As a European, it never happened to me and if I think about doing it myself it just seems creepy and weird.
That’s probably it then. I’d say it feels weirder in America if you’re completely shut off to random small talk. It varies a bit by region, and certainly by individual, but I’ve never been anywhere in America where it’s strange to strike up a conversation standing in line or waiting for a bus or something.
America is huge huge, there are several different norms across the country. The people who live in the Southern states have a wildly different approach than people who live in the Pacific Northwest, for example.