Editor's note: This column is part of 'Why Do We?' — a weekly video series hosted by culture expert Martin Lindstrom that untangles unique quirks of human behavior. Click here for the full series page ...

Let's be honest, shall we? You have pushed the 'close door' button in the elevator, whether someone was coming or not, because you just want to keep moving. Hey, I've done it and I'm not ashamed to ...