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 think it’s important to separate “polite” courses of action from a polite manner of choosing a course. You shouldn’t feel the need to join a conversation you don’t want to just to be polite, but you should be polite in your rejection (as OP was).
Women don’t have to be polite in their rejection especially when they are feeling uncomfortable.
Fuck Politeness is about putting one’s own safety above other people’s feelings.
Nobody has to be polite. It is simply good to do as long as it does not negatively impact safety.