MY HUNGARY GAMES
I had three of them both in EU3 and Eu4 and all of them were magnificent Screw Ups

Really, I played many countries and I always create fun empires even in Africa but I hate playing Hungary so much...
HUNGARY GAME NUMBER ONE, EU3
At first it was going nice. No, at first it was going perfect. I somehow managed to initiate great war of something like 20 - 25 countries against Ottomans

(with me + Poland being initial ones) and completely ravage Ottoman Empire before 1444 so it never was a threat.

Later my Hungary included the ENTIRE Balkans except few coastal/Greece provinces and my vassal, surprisingly strong Bulgaria.
It was fun and I had magnificent cavalry. I started joining Venice in Italian Wars. And oh boy believe me, they were the most dramatic wars ever fought in EU vanilla Italy

the entire peninsula was burning like 4 times but finally my ally Venice dominated entire northern part while I had southern part.
So, where the Screw Up happened?
...
I have absolutely no idea how I managed to overlook such major thing but suddenly I realized my country has Eastern group, really poor provinces (Balkans...), 5 religions, like 10 cultures, no positive tech modifiers aaand guess what.
I somehow managed to turn Hungary into literally the most technologically backwards nation in the known world. Not only in the Europe, but also less technologically advanced than freakin Tatar Hordes, Mamluks, Arabia, Timurids and even some South East Asian
states if I remember properly
Amazing achievement
This was one major screw up. Second major screw up was my brilliant Italian foreign policy which suddenly turned Venice into superpower much much stronger than me. I mean, I created idiotic situation when
I have a country covering the entire Balkan Peninsula + Hungary + Austria + Sicily and I have less income per month than Venice covering northern Italy. Not to mention them being naval superpower, trade superpower and of course technological superpower. They would be crushed by alliances but I literally gave them Italy. The more I was desperately trying to modernize, the more I was backward and the stronger Venice was becoming. Finally I left this humilitating game. (although if I had the save currently I would play it just to observe epic incoming collapse of my pathological state)
HUNGARY GAME NUMBER TWO, FIRST GAME IN EU4
Soo I bought EU4, understood basic concepts, and decided to try Hungary. Hey, I have an experience with this nation, I though, right?
Yes but not in EU4.
I fell in love with EU4 despite Paradox completely destroying my state and my soul. I mean, for some reason I had insane problems with rebels. And I mean INSANE. I have never been playing so failed anarchy state as this Hungary. I don't remember myself having extreme difficulties with Austria/Ottomans/Poland, I mean I had difficult wars with them but it was not them who devastated me in this game.
Rebels...
I had peasant wars. Countless peasant wars. Heretics. Doubling stacks of rebels. Pretenders. Religious uprisings. Noble rebels. Nationalists. Patriots. Literally every goddamn kind of rebels possible for this period and place. And most of all, these goddamn
Serbian nationalists. For some reason I decided to conquer Serbia and this was major Screw Up: not only provinces were poor but Serbian rebels were always ready to siege 1/3 of my country. Second screw up: I released Bulgaria from Turkey, declared war on someone who was allied with Bulgaria and voila, I have created myself another challenge. And these Bulgarians were absolutely crazy in their will to destroy my state. Combine all these factors and
I had situations when half of country was occupied by foreign forces, 1/4 was occupied by rebels, few other provinces were sieged, I had no manpower, 5 loans in the same time, negative stability, on the border of bankrupcy, no available mercenaries and with one last army with some good general. If I remember properly, I was molested by Venice, Bulgaria (lol), Austria and Bohemia and believe me, it was enough. I had 50 years of 'short peace - rebellion - invasion - rebellion - invasion - short peace' cycles and I finally was so exhausted I left this game.
HUNGARY GAME NUMBER THREE, SECOND GAME IN EU4
Ok. This time my country was epic. Most of Southern Europe under my 'sphere of influence'. Strong country. Good technology. Alliance with absurdly strong Poland (despite wars with Lithuania!). This time I screwed up because I somehow managed to be overplayed by AI.
This Sweden...
Sweden:
1) United Scandinavia
2) Completely massacred Russia
3) And Germany
4) Became the top technological nation of the world
5) With ridiculously strong army
6) And the best generals I have ever seen...
This was insane. Sweden was declaring war on Poland along with his ally Lithuania (sic) and few other lesser countries. We were doing nice until major Swedish stack arrived. Then we were dead. It doesn't matter if our armies were 2 times bigger, if I was trying scorched earth, hiring countless mercenaries, best generals, nothing: when Swedish Stack arrived, with some absurdly powerful general, it was conquering half of Polish empire, going to my Hungary, crushing resistance and hunting my last desperate armies
in Serbia (!) then returned to crush Polish armies again and generally completely f*** us...
Abandoned this game.