Common phenomenon

So here it is. We've all fallen victim to it, and we've all knowticed it and chuckled a little to ourselves as we watch people pass by. What is it about being in the car that leads people to belive they are completely invisible to the people stopped beside of them at the stop light, or strolling down the street. What is it in that container of metal, plastic, and glass that makes us feel secure enough to scratch that questionable itch that's been bugging us all day, or dance in our seats like a seizure victim while singing at the top of our lungs to lyrics we 'sorta' remember.
I was pondering this queer fact for perhaps the 50th time in my life as I sat in our store window repairing the paint on our window sign that someone decided to scratch away. I peered through the "B" for a moment only to come into direct, uncomforatable eye contact with the woman stopped in her car at the stop light, staring at me. She must be a champion at staring contests with her little niece and nefews, she was quite good. I quickly diverted my attention back to what I was doing, stealing another quick glance up, yes I'm still being watched.....How long does this light last? Feeling like a fish in an aquarium I stared back to see if she would turn away. Nope didn't phase her at all, someone grab the woman a hot dog and a soda, she's in for the long haul. Finally, after an eternity of unease, the light mercifully turns green, and the woman roused from her deep observation, pulls away completely unaware of the fact the local barista was having a wensday afternoon staring contest smack-down with her. She was the unwitting winner. What is it then, in that little bubble of cash sucking transportation that makes us temporarily live in some other, strange, new world where we are the only inhabitants?