answer:I interact briefly, and loudly, eg “YES, IT IS A NICE DRESS ISN’T IT?” as I firmly walk away… Or, if I am not in a situation where I can’t walk away, I just give a half-hearted half-smile, a backwards nod, and look out the window… If they’re really persistant, I will have a conversation, but again, loudly… quite interesting people some of them :-) I’m sounding like this happens to me a lot, ha ha! I am someone that makes eyecontact with people, and generally quite smiley so I guess I must seem approachable!