Diplomacy, however, you can't manage any attacks by yourself. You will either depend on someone helping you with an attack/defense, or you will have to trust that someone doesn't attack you as you overcommit. You don't just verbally agree to these things, either.
Every turn, players commit to writing what they are doing and all the moves are resolved at once. So a player can go from imagined victory to catastrophic betrayal in the reading of a single order. This means that someone was just lying to their face for 15 minutes.
Some people just can't handle that.
Oddly, being branded as a backstabber just entices others to try to use that backstabber against what they see as a common enemy.
Best game ever. (I only behave like this in game, I swear!)