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.
‘I’m not really here to talk’ and leaving isn’t rude at all, don’t sweat it. If you had screamed at him that he was a creepy POS or something then you’d have a good reason to feel bad if he had some kind of intellectual/developmental disability, but you didn’t, and even if he does there’s a point where you have to learn you’re not a cute kid who can just walk up to people at random and start talking to them anymore (or at least not have everyone be as receptive to it).