King Kalmah
Magyar Madness
Well they have tried to genocide each other numerous times. I can see how that can seed a little resentment.
100 years ago nationalism in ones nation was king and hatred of all neighboring nations was mandatory...
plus who could blame them when the majority of the time it was the neighboring country who either stole land from them or made war or culture whored all the nice stuff...

In all seriousness I have a lot of relatives that live in Croatia since after the split from Hungary they were too rooted in their villages to move and who can blame them.
The half of my family that is Hungarian is only Hungarian by a few miles...(G-ma's farm is right on the Austria-Hungarian border) and my Grandpa is from a major center of industry in the southwestern section so his ancestors may have been Croatian...plus he always told us about places along the Croatian highways which were dangerous for tourists...mostly since the Iron Curtain had just fell and a lot of stupid tourists were getting robbed(he avoided trouble since he spoke Croatian/Croanish(spelling) and served in the Hungarian army so he was no wimp)....probably calmed down by now...