Agreed that Diplomacy is tremendous fun, as long as you have 7+ hours to spare and a house with lots of separate rooms for private conversations to take place in. But the important thing to keep in mind is that the only way to win the game is by first making alliances with other players by promising you would never betray them, and then second by strategically betraying your allies before they can betray you. If everyone goes into the game knowing that betrayal is the point of the game and that they will be stone-cold lied to by their dearest friends, then there's no hard feelings. But if you're a brand new player and this metagame isn't properly expressed to you, then it's natural for fallout to ensue.