At first I wondered why Hitler wanted to conquer Europe, which led me to the treaty of versailles, which was a 'good' political reason for Hitler to spark the Second World War.
So then the treaty of versailles and World War One, I asked myself where WWI came from. This led me this page, which introduced me to Austria-Hungary and Serbian relations being funky. This led me to this webpage, which states:
Austria-Hungary, which was a dynastic empire comprised of MANY different races - it was nicknamed 'the polyglot (many-languages) empire' - was terrified of the 'panslavism', the nationalism by which the Slav races of the Balkans aspired to set up their own nation-states. Austria-Hungary regarded Serbia as the leading, and the worst, example of this. Austria-Hungary HATED Serbia.
This was 1804.
Now my question is: WHY did Austria-Hungary HATE Serbia?
I don't understand the why behind the hate that eventually led to the second world war.
Can anyone explain it to me?
Austria-Hungary actually had a pretty decent relationship with Serbia up to the murder of King Alexander I (of the House of Obrenović) of Serbia by the Black Hand and following coup 1903.
Both nations had a common enemy in the Ottoman Empire for most of the early part of the 19th century, and it was not until the murder and coup that Serbia started on the path of Greater Serbian Nationalism. This was aimed towards Ottoman Kosovo, an alliance with Montenegro and ambitions against Austro-Hungarian Bosnia (de facto under Austro-Hungarian control since 1878, formally annexed 1908) and Hungarian Banat (today part of northern Serbia) and Croatia.
The Croats, Serbs and Bosniaks (the latter can be argued a bit, but still) were not the only Slavs in the Austro-Hungarian Empire. There were also Ruthenians, Poles, Czechs and Slovaks (although the Poles were less than thrilled about pan-slavism).
Nationalism was a threat overall to the multiethnic and polyglot Austrian (and later Austro-Hungarian) Empire. But pan-slavism was a larger threat than any other. Since Russia was the main instigator behind pan-slavism, and an ardent supporter of Serbia and Serbian expansionism, pan-slavism threatened Austria-Hungary on several fronts. Not only the grand power of Russia, but also the expansionist Serbia with its ally Montenegro, but also possible revolts from slavs within the Empire.
The Austro-Hungarians new there were other nations cirkling like vultures. Romania wanted Transylvania. Italy wanted Trentino, Trieste, the Istrian peninsula, Pola and Dalmatia and so on.
Serbian expansionism was a very real threat, and people like the Chief of the Austro-Hungarian General Staff, Franz Conrad von Hötzendorff argued that only a war could resolve these issues, and that with a powerful Germany at its back, Austria-Hungary should take Serbia and Montenegro out to crush any Balkan nation supporting pan-slavism.
What is ironic is that the Austro-Hungarians actually were pretty popular in the areas that Serbia coveted. The Croats had sided with the Imperial Government against the Hungarian rebels 1848. The Serbs in Bosnia, along with Croats and Bosniaks had experienced a much better administration (that had built roads and railroads, eradicated banditry, improved the local economy, established a reliable post system and built telegraph and telephone network and established order and safety) than under the last decades of Ottoman rule and were appreciative of this.
Archduke Franz Ferdinand and his plans for the future of the Empire, with increased influence and local self-rule for all peoples in the Empire (at the cost of the Hungarians mostly), first as a confederation or quadruple monarchy, later as a federated Empire with centralised parliament was also very popular among the southern Slavs of the Empire. That was one of the reasons the Black Hand attacked him.