the (AI) message "Nation X has declared war on your unholy nation"

[Saxon]

I always used to grumble when they called me Unholy. However, when playing a undead lizard lich instead of my usually goodie two shoes, I took it as a compliment!

Galactic Civilizations had pretty good diplomacy, though the trade system associated with it was a bit of a cash cow. Most other games have been pretty weak, until you got to multiplayer. Then it all depended upon your opponents.