Only grief comes of war IMHO.
Today technology enables war to be fought without trenches, firearms, or soldiers. DEWs and other means of mass destruction enable the murder of enemy troops or societies without deploying troops at all. The only reason troops are necessary today are to control societies, or if the combatant does not have access to nominal WMDs.
This is why I incessantly beat the drum of independence of means of individuals from centralized economic structures. Overlords will not supply individuals with WMDs nominal to defend themselves against overlords' forces, so for individuals to be free they must themselves supply their WMDs that render armies obsolete, and overlords vulnerable to the same murder they inflict on their subject peoples.
Thanks!