while it's true that many really creative, intellectually amazing people come off just as you described... so do mentally disturbed people who are not safe. I'm of the mind to do nothing at all...except to wait and see. the Scottish method has worked for me for years.
Act like you are deaf and do a little sign language and ignore them. It works.
tell 'em I don't talk to Mormons!
Let them speak, nod, smile, and if it interests you, carry on the topic. If not, politely tell them you have to be on your way
listen and talk with them and happy that I learned something
Talk to them like you would anyone else, no one likes to be labeled.
What exactly do you mean by disturbed?
Try and stay calm, and defuse the situation by walking away. First make it clear to them that is not appropriate, and then walk away, sometimes situations like this its best to walk. Do not aggravate them to become worse.
i talk to them, usually
talk to them I have made many friends from people that freaked me out at first