The whole lead up to WWI reminds me of the lead up to a school yard fight and the apportioning of blame similar to the aftermath. With this in mind I present to you my schoolyard version of WWI:
There are 2 main gangs in school, the Central Powers and the Cordial Alliance. The central powers consist of Germany, the toughest kid in school, A-H who fairly big and strong but is known to be poor fighter and the new kid Italy. A-H and Germany do not trust Italy as he has been seen smoking with France behind the toilets. It turns out that they are right about this. The last member of the Central powers is Ottoman, who smokes, has asthma, ricketts and a complexion that would make the average nerd on an internet history forum wince. No one takes him seriously. The Alliance consists of France, who used to be the toughest kid in school until Germany beat the stuffing out of him last year, and Russia. Russia is big, fat and strong but does not know how to fight, depending on big haymakers to knock the other guy out. Britain has started hanging out with France recently, although he doesn't really like him much, because he is afraid of Germany. Britain does not like fighting and would much rather just intimidate the little kids into giving him their lunch money.
A-H decides he will nick Russia's little brother Serbia's lunch money after somebody hit A-H with a piece of thrown fruit and A-H decides to blame Serbia.
"Hey, why'd you throw this at me you little twerp? I think you'd better make this up to me now, an' I'm feeling hungry..."
Russia, seeing little Serbia about to start crying storms over and grabs A-H by the collar shouting "If you so much as touch 'im I'll f***ing do you"
A-H looks around nervously and sees Germany striding up. Germany thows an arm around A-H's shoulder an says "I've got your back mate. If any of these **** heads try anything I'll ****ing smash 'em.
A-H full of renewed confidance turns to Russia and grabs his collar back. Russia and A-H stand face to face going "Yeh go on.." "yeh I'll take you" "you wanna try something" "yeh?" "yeh?" YEH?"
France hearing the raised voices and eager to get some revenge on Germany runs over with fists raised. Germany, slight panicked by the sudden increase in tension suggest in a quiet voice that A-H should "maybe calm down a bit" but A-H is way to angry at this point and just ignores him. Germany turns to see Britain standing close by and geastures a question about whether he will get involved and Britain replies with a non-commital gesture which Germany assumes means he will not get involved. Taking the opportunity before France is actually ready for the fight, Germany throws a sucker punch right into Frances jaw. Outraged at this breach of Marquess of Queensberry rules Britain throws himself into the fray, and the fight is on for one and all.
In the end A-H is carried away unconscious, Ottoman has collapsed with a severe asthma attack after being punched in the solar plexus, Russia has retreated to the corner crying over a broken nose and Germany has been suspended from school. The 'winners' Britain and France, are both nursing a range of injuries and swearing that they would never let another fight like this happen again.
So, who's fault was it?