https://en.wikipedia.org/wiki/Ten-Day_War
NATO bombing was not out of the blue. The head of Yugoslavia was a similar mad man (to Putin), just warring out of desperation. The best proof one has of his lunacy is the fact that Montenegro split from Serbia without any deaths. How did this happen? Due to the mad man dying in 2000. I'm pretty sure he would have enacted order by butchering civilians again, inside "his" borders.
Serbia is also the only country out of these conflicts that does not guarantee seat in the parliament for the exYugoslav minorities. Even though the leadership displayed aggression that was successfully deflected, the defenders made a deal to guarantee inclusion of the Serbian minority in the parliament (Croatia, Kosovo etc.)
Still, we have a country like Germany, that self-flagellates for decades and the sentiment of the majority is quite clear. While the general sentiment of people/press in Serbia is that NATO bombing is equivalent to Putin bombing Ukraine. and yeah, every now and then, the most popular Serbian (Monacoan) tennis player will say things like "Kosovo is Serbia" with complete indifference and still be the Jesus like figure his father makes him out to be.