On many occasions when I meet someone new and get talking with them, they almost always throw the "where are you from" question into the conversation. 
"Are you from here?" They'd ask. Then I'd answer, "yes." 
Sometimes I ask why they asked. Sometimes, I don't. But when I do, I usually get a response along the lines of: just curious, you don't look like you're from here, or I didn't think you were from here. It makes me wonder how one can tell you're from—or not—from somewhere. And when you ask how they know, they simply say, "I just know". 
So if scripture tells me that I'm IN this world but not OF this world, how much of a reality is that word in my life? Is is supposed to be so apparent that they "just know"...