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.


Yes. Some people, including women but more often men, will initiate a conversation in a way that puts the other person on the defense which prompts additional interaction. While saying “I haven’t seen you here before” could be an icebreaker while pushing buttons on an elevator at an apartment building saying it after rushing up and sitting down next to someone who is looking down is basically invading someone’s personal space when they weren’t ready and comes across as pressuring for a reaction.
I had the same thought at first until the last sentence that said how quickly he approached and sat down. If he came in slower, asked to sit next to her, and if she said yes he said the same thing it would be completely different. I’m a dude and I wouldn’t want someone rushing to sit down next to me and start a conversation when I was looking down at something.