I generally keep to myself as I’m fairly quiet, but I’ll talk if someone gives me something to talk about (though small talk makes my head hurt).
My dad is exactly the opposite. He will find something in common with absolutely anyone and will know more about them in twenty minutes than I would in 20 years.
I can be both of these things. I could sit in a pub watching a game or whatever and not say a word, or could get into a conversation with the person next to me that turns into a real deep conversation about what life is about.
Generally not a lot of dialogue with the general public. If I'm in a store, it's get in, get what I'm there for, get out, and I tend to keep most co-workers as just that.