I grew up playing this game in high school. I was first introduced at a gaming club after school and quickly learned how backstabbing and breaking promises worked.

One of our club members and a "friend" I have known now for almost 30 years told me he would support me if I attacked another player. I committed my troops but he did not send support. When the turn was over he told the other player that I must be crushed because I could not be trusted. I shouted, "You told me to attack him and that you would support me!" To which he replied, "You are a lying Brit and you should have your tongue cut out!"

http://news.msn.com/obits/diplomacy-game-inventor-allan-calhamer-dies?ocid=ansnews11