The first World War was Serbia's fault, since they refused to hand over the Assassins who killed the Crown Prince of Austria-Hungary, at the time our ally. Obviously they declared war on them. They (the Sebs were guaranteed by Russia who declared war on AH and we declared war on Russia, because AH was our ally. France declared war on us since they were allies with Russia. And Britain joined in too after we invaded Belgium to flank into france.
The Second World war.... yeah we got no excuse. It is a shameful period in German History.
Also we have come a long way from then, and ironic isn't it. That the vountry whi started a world war and basically fought another one all on its own would come 75 years later and say, Force is not the way to go?