Can people read other people?

That is a question I ask myself frequently. I want to say, "Yes". Some people tend to be an open book, while others just confuse and bewilder me. Today, while at the gym, I was talking to a friend of mine, when someone I didn't know simply came up and started a conversation with me. Later, my friend commented how she thought that was odd. But, it really isn't odd for me. That happens to me all the time. I love to talk. Can other people who love to talk tell that I also love to talk? It is not uncommon for me to have a lengthy conversation with someone at the store that I have never met before. In fact, last year I bought something on eBay. I sent the lady an email letting her know that I had made the payment and thanked her (in advance) for the item. She sent a reply that went into detail about the plans she had for her day. (Now, that was a bit weird to me).
But back to the question..(Can people tell I love to talk) or, does my willingness to speak in response to their initial question simply encourage the conversation further? So in other words, they didn't know whether or not I would engage in a conversation, but they try it with many people? I don't know. Mark, what do you think?