CELL PHONES...especially the hands free type that you can hide with longish hair. You can't tell if they are talking to you or just mentally deranged.
There can not be that many important people in the world needing to recieve that many important messeges that they need to be on their cell phones constantly.
...and just in case you're interested, I don't have one. So, if you see me jabbering to myself in the middle of the WAL-MART parking lot, go ahead and call the little men in white jackets.