Well, INTJs do not usually hang out in large crowds, and if they actually do, as some of the INTJs mentioned earlier, will stay at the periphery. We generally like to stand from a distance where we can observe happenings. I myself love to do that. It gives me satisfaction being able to understand social interactions between people i know. I assume INTJs don't really like to go out, as I do not go out unless absolutely necessary. We are usually poker faced... Not really adapt with expressions i guess. Lastly, personally I happen to smile in the public sometimes when i notice something funny or weird that I didn't realise all the while. It comes across to my friends as freaky or some sinister plot hatching freak, apparently.