For real, war is a childish act of leaders who want to show their powers against each other instead of channelling that energy into something that will make the world a better place.
It's a pride game. It's true that they're acting childish and can't even let just pass it when other countries are living peacefully. To show off their power and military strength.
Why do we need weapons when everyone can leave in peace and unity, I do t think those interests shared by some world leaders as reasons for the war are not worth it and nations should negotiate more instead of drawing limited lines for each other.
While some countries achieved to do this, in every time of different generations. There will always that someone who won't allow people to live in peace and harmony.