I'm sure those Christians around the Balkans would have much rather been a part of the Holy Roman Empire that were nothing but kind to the Orthodox.
Turkish slavery/occupation is perceived as much, much worse in folk memory than the Austrian. Of course, both of these are foreign empires, so neither of them is good, but one is clearly worse than the other...
... The parts of Serbia that Austria-Hungary didn't conquer by force about a hundred years ago were more developed than the parts they did conquer by force? Clearly the Ottoman's fault.
https://en.wikipedia.org/wiki/Serbian_Campaign_of_World_War_...
Austria-Hungary fought with the army from and occupied during the World War I the Serbian "territories" (inhabited with the people who massively died during the occupation) that dragandj says are still "less developed" today:
From the Wikipedia article: "The estimates of casualties are various: the Serb sources claim that The Kingdom of Serbia lost more than 1,200,000 inhabitants during the war (both army and civilian losses), which represented over 29% of its overall population and 60% of its male population,[14][15] while western historians put the number either at 45,000 military deaths and 650,000 civilian deaths[16] or 127,355 military deaths and 82,000 civilian deaths.[17]" The numbers are all over but whatever they are, they are huge for a small country. To compare with something that happened around the same time:
https://en.wikipedia.org/wiki/Armenian_Genocide
"The Armenian Genocide (...) also known as the Armenian Holocaust,[9] was the Ottoman government's systematic extermination of 1.5 million Armenians,[note 2] mostly citizens within the Ottoman Empire." "Date: 1914–1923"
In WWI Austria-Hungary attacked Serbia and that's how the WWI started. It did a lot of damage to Serbian state. But this is 100 years after 1804, when Serbia started a process of breaking off from slavery under Turks. By the mid-19 century Serbia was practically independent.
I am comparing two areas that have been under foreign Empires for a long time. The area north of Danube and Sava was only briefly under Ottoman rule, and then was conquered by Austria(+Hungary) while to the south of Danube and Sava was under Turkish rule for 300-500 years. Not only Serbia, but also Bulgaria, Macedonia, Albania etc.
All the areas that were ruled by the Turks are backwaters even to this day, the areas to the north much less so. There are other factors, of course, but everyone from the Balkans clearly recognizes this (development) dividing line.
WW 1 and WW 2 came later and brought its own share of destruction, but that destruction came after the nations were formed here, and the distinction I'm talking about have much older roots, that can still be clearly seen, even in how the towns and cities are laid out, ways of doing business etc.