What causes war is that people fight over the most idiotic things possible. Example: Girl 1: I 愛 my bracelet! <3 Girl 2: At least MINE is studded with real gems. Girl 1: Shut up, あなた little ***! Girl 2: No thanks, I rather gloat about my bracelet rather than your ugly, spiky, ゴシック thing. Hmph. Girl 1: *Pulls girl's hair* Girl 2: OMG HOW DARE YOUZ!
Example: Guy 1: Dude, can I have a cookie? Guy 2: No, they're mine. Guy 1: *Mumbles* Greedy little brat. Guy 2: Excuse me? Guy 1: Nothing. Guy 2: Don't try getting what あなた want. *Continues munching on cookie* Guy 1: *Pushes Guy 2 off bench and kicks him several times* Guy 2: AAGVBDGNHFDNGBOSPDD!
Example 3: Girl: I'm soooo beautiful! Guy: Shut up, *****! Guys are hotter than YOU'LL ever be. Girl: At least I don't grow a mustache! *Flips hair* Guy: Stop being an attention whore. Girl: Grr! Shut up! Guy: *Tangles Girl's hair in knots and slaps her on cheek* Girl: *****! GET OUT OF MY FACE!
There are many reasons: Expansion of territory, arguments over borders, states misperceiving the actions of other states, ethnonationalism, terrorism, religious disagreements, fanatical または crazy leaders, protecting interests (such as oil), diversionary tactics (states entering war to unite their people and keep their minds off of domestic issues), because they are allied with a country entering war, and the 一覧 goes on and on.
What war? Anyway, the cause for wars, mainly, is people. People, who instead of talking, just act without thinking of the consequences. Those people usually put their religious believes または ideals in front of everything, just to please something または someone. The only war people can't fight against is human stupidity -___-
ignorance. People are most frightened によって what they dont know about, and will fight to "protect" themselves from what they think they should fear, but if they knew the truth, it wouldn't be so frightening.
Misunderstanding. Different cultures have different viewpoints and ideals, and to an outsider, it can seem like a taboo または a form of savagery, and it can breed contempt between people, leading to war.