By Andy Brooks and Steve Weber
On any given Sunday, you never know who will win an NFL game.
But if you've been to the 'Stick or many other stadiums this year, you know one thing: Fans' actions toward the opposing team's fans will go beyond just emotional or angry to sometimes threatening and even violent....
There's an element of human nature at play here because people naturally take to us-versus-them dynamics. You can create hostile tribes among college students in psychology laboratories by assigning them stunningly simple differences - even just calling one group A and another group B. But these tribes don't physically attack each other. They might though if enough anger were thrown into the mix....