NT, Bulgaria is always the Problem 0/8
Serbia attacked Bulgaria 1885 during our Unification with Eastern Roumelia whilst the whole Bulgarian army was situated on the Turkish border waiting eventual Turkish attack because we are taking their territory not Serbian. 20 days later, the Serbian Government licked Austrian Hungarian boots because the Bulgarian army was in the center of Serbia kicking Serbs asses and they were close to total destruction so the Austro-Hungarians said that if we do not stop, they will intervene.
Before the First Balkan war, there was a contract if we win against the Ottoman Empire which parts will be added to which country and of course after the war even though Bulgarians fought the biggest battles in that war were fucked up by Serbs and Russians, Serbs said, "We are not giving anyone back what we conquered" although there was a contract signed a year ago. And Serbs started brainwashing the population of nowadays NOrthern Macedonia that they are not Bulgarians.
During the Second Balkan war Serbs had to lick again this time Russian boots after the Bulgarian army started counter offensive on every front and the Russian Government forced Romania to intervene.
But both Romania and Serbia got what they deserved in WW1
Bulgarians were the majority in the Balkans, that is proven by Ottoman sources from that time, the strongest army on the Balkans at that time. Amazing times, we would have whooped all your asses 1v1