What made me think of this was the video mamboni posted where random passers-by are asked to guess the price of gold. I was struck by how many people would not even break stride for a second to talk to him. It probably had nothing to do with gold.
As long as I'm not in a rush, I'm happy to talk to anyone about anything, pretty much any time. I don't mean disclose personal information, but just share opinions or comments or humor on things. I enjoy interacting with people, and hearing what they have to say. I have a friend who, when we are out somewhere, will inevitably get us involved in a conversation with a group of whomever happens to be within earshot. His knack for this is amazing.
How about you? If you are at the store or a ballgame or a bar or a movie, do you like getting engaged in conversation with strangers? Or are you uncomfortable and would rather avoid it? Or neutral? As a self-test, if a stranger opens up a conversation with you, do you usually try to keep it going, or do you tend to cut it short because you prefer to be left alone?