Personally...I think they go to war because they get bored. That's why I go to war whenever I play Civilization 2...and look at me. I have conquered the Souix, Japanese, 90% of the Persians, 90% of the Vikings, part of the Aztecs, and 50% of the English. My navy consist of 17 battleships, a cruiser, and about 3 submerines. I have 2 aircraft carriers with full of fighters and bombers. And I have an ample amount of transports to carry around my armor, cavalry, marines, paratroopers, etc.
Its all because I get bored with peace in that game. I think it is the same reason why people go to war in real life.
Example:
President: "What to we have to do today?"
Secretary: "Well, the budget needs a little work...The senate wants a bill passed...and some people are protesting the building of that new road..."
President: *SIGH* "Hey...Lets go to war!"
See?!? Thats how it is...
