Why was germany a big pain for the allie power

The Germans spent more money on the army and equipment but after that the Germans went bankrupt. They cut many cost of germany's goods and focused on military 

Derivation of Central power in ww1

At the central power at ww1 there was Germany , Austria-Hungary , Ottoman Empire and Bulgaria. Why did they join the Central power in ww1 

Germany 

The Germans always wanted to dominate Europe economically and politically , as the Germans saw an opportunity of war they took it and invested in the army and joined the central power. They joined the central power as they had a good alliance with Austria-Hungary. It all started at the 1879 alliance where the German empire  and Austria-Hungary were aligned to handle the attacks from the Russian empire. That alliance made them very close. Incase they joined the central power somehow there alliance with Austria-Hungary  

Austria-Hungary 

As germany did not join allied power to not break alliance and trust with Austria-Hungary , thus even Austria-Hungary  did not want to break that trust and alliance also Austria-Hungary  did not like countries like Britain , Russia and France 

Ottoman Empire 

The ottoman empire also had an alliance with Germany which they did not want to break as the Germans were quite powerful as they spent a lot in the army. Also the empire had surprisingly attacked Russia in 1914 , why ? One of the reasons is the German influence of attacking Russia , also there were provocations that said “ the ottoman empire’s government failed miserably in war , to show their bravery they surprised Russia by attacking the black sea coast of Russia. They also wanted future control over Russia 

Bulgaria

Bulgaria depended on the trades with Austria-Hungary and the ottoman empire , as they did not want to lose that trade they joined the central power at ww1. They thought before incase if allie power lost to central power austria-hungary and the ottoman empire would take it as a betrayal