Manners

The analogy for me is of being in a pub, on your own and seeing a group of friends, talking loudly and having a good time. You notice that they are talking about something completely fascinating that you want to talk about. Would you simply go over and start talking to them, without introducing yourself? Without assessing whether they look friendly or like baby-killers? If they are very polite would you talk to them in a coarse, vulgar manner, f'ing and blinding? What about the reverse?
I would (and do) happily talk to total strangers in a pub with nothing more than a brief introduction of, "Hi, I'm Object...........................RANTRANTRANTRANT". It works beautifully for me.