Please don't start nationalistic flamewars on HN.

I realize the OP has some overlap with inflammatory content but that's not a reason to start flamewars, it's a reason not to start them.

https://news.ycombinator.com/newsguidelines.html

People of ex-Yugoslavia have a slightly amusing trait that they overestimate importance of their local history and its impact on the world history. You'd think Abraham Lincoln was picked to be the US president by a commitee from village of Crapski 113km southeast of Zagreb. This excessive pride in obscure, embelished and unimportant historical events is probably one of the reasons for animosity between peoples of the area. If they were half as smart as they think they are, they'd be long united and speaking the same language, like wiser nations such as Germans, French or Italians. But they're not, hence the hatred.

I am not sure what you mean by "started", the region was at the intersection of big empires that fought each other and the people there were caught in the middle trying to survive by chosing the least worse of the empires.

I would say the conflicts are started in the capitals of the big empires/powers.