the big web of politics and such just gave me more questions.

Well that's the answer itself, in short. I answered to the similar question ages ago, so i will basically just modify the same answer here, using same sources. Warning, it cannot be a short or simple answer.

Reasons, as you got to see yourself, are very numerous and complicated, many roots of the problems go back to 1918. and finding of Yugoslavia, but that's too complicated for someone not very into the whole Yugo stuff.

So, SOME of the main reasons, simplified, as objective as possible, in chronological order, in 20 years preceding the dissolution:

Croatian spring; For many people the usual starting point is 1980 and the death of Tito. But the roots of dissolution can be found much earlier, in the 70's. In 1971, after 25 years of existence, Socialist Yugoslavia experienced the first outburst of nationalism within its borders, so-called Croatian spring, openly opposing unitarization of the country and demanding bigger federal rights for Croatia (and thus other republics too). Although the ''Spring'' was quelled, this is an important event because it effectively marked the death of an idea of unionist, ''Yugoslavian Yugoslavia'' ( Long term goals until then were that sometime in the future, ethnic groups all melt into a ''Yugoslav'' ethnic group, so ''Yugoslav'' was an option on population censuses from 1960's on, but never really got popular). From Croatian spring on, it was clear that the federation was the maximum level of unity Yugoslavia could achieve, and that despite everything, national/ethnic interests were still strong and would remain so.

Constitution of 1974 and decentralization; After many years and a lot of debates, new constitution was created - it started the trend of disuniting the country, because the constitution introduced a concept that sovereign rights were exercised by the federal units (republics), and that the federation had only the authority specifically transferred to it by the constitution. Moreover, two autonomous provinces, both located in Serbia (Vojvodina and Kosovo) were effectively given a status equal to the republic (though remaining Serbia's provinces), being taken out of the Serbian sovereignty. This was extremely controversial in Serbia and led to protest from many intellectuals including the famous ''walk out'' out of Belgrade University Faculty of Law in 1974, because of which many professors got fired. Beside the stated problems, constitution itself was incredibly cumbersome, badly written and generally complicated. So, the way ''Croatian spring'' stoked the first flames of nationalism in Croatia, the infamous 1974 constitution did the same in Serbia.

Death of Tito; In 1980, Tito died without effectively leaving the system to succeed his position. He was succeeded by the ''presidency'' made of representatives of every republic and autonomous province. From this point on, Yugoslavia was effectively more of a confederation than a federation, and the trend will only continue during the 1980's. Add on top of that a whole new class of politicians, lacking ideology and mostly self-interested.

Uprising in Kosovo; In 1981, in Kosovo, Yugoslavia's poorest region, Albanians started the rebellion, which marked the first ethnic nationalist uprising in Yugoslavia (Croatian spring was more in the form of protest and cultural manifestations - While situation in Kosovo led to rioting, arrests, and emergency situation). Moreover, Serbs in Kosovo felt that situation wasn't handled the way it should have been, and longed for the return of the province under the full control of the republic as it was before 1974. This kind of domino effect of nationalism would appear in most events in Yugoslavia.

Economy; Parallel with all this, economy should be mentioned before i move on - by the late 1970's, economy started stagnating, even occasionally falling into recession during the 1980's. Yugoslavia was heavily in debt, unemployment was chronic since mid 70's, and by mid 80's inflation was serious. This long slow descent culminated in the collapse of the economy in 1989-1991.

Serbian nationalism rebirth; In 1987, Slobodan Milosevic was elected as the Chairman of the Serbian Communist Party (Branch of the League of Communists of Yugoslavia - see, even the ruling party was confederalized and separated by republic lines). Appearing as the populist strongman, he vowed to calm the situation in Kosovo. In the worst timing ever, in 1989 came the 600 year anniversary of the Battle of Kosovo (1389) which is one of the central elements of Serbian patriotism, art, epic poetry and national consciousness. On the anniversary day, 28 of June, Milosevic held a huge gathering on the site of the battle, which attracted hundreds of thousands of Serbs. This symbolically marked the moment Serbian nationalism was fully woken up.

Slovenian separatism; Parallel with all that, Slovenian separatism was slowly rising through the 80's, for a different reason - Slovenia was the most prosperous republic, closest to European Community and least hit with the economic troubles of the 80's. As the idea of Yugoslav unionism slowly waned among all nationalities, Slovenians were the first to take effective measures of leaving Yugoslavia.

14th Congress: In the unfortunate timing of communism falling in Europe, the League of Communists held the 14th Congress in January of 1990. Congress's goal was to determine the future of the country. Serbian delegates led the ''unitarization'' faction, while Slovenian delegates led the ''confederalization'' faction, trying to transform Yugoslavia into a pretty lax union of six sovereign republics. The congress, in short, was a total mess, and ended with Slovenian delegates walking out, and Croatian delegates following after them - this marked the end of the League.

Multiparty system divided by Republics; In the aftermath of the disastrous congress, it was decided that multiparty system would be along the republic lines. Through 1990, republics had their elections, starting with Slovenia and Croatia and ending with Serbia and Bosnia. In Slovenia and Croatia, nationalist separatist parties won. Bosnia is a complicated story because it's effectively a ''Small Yugoslavia'' with three ethnicities each giving their representative - but anyway, among the Bosniaks and Croats, separatist options also won. In the rest of republics, unionist parties gained power (usually reformed ex-communist parties) while nationalist options were in opposition (this was true for Serbia too, where SPO, the party propagating Greater Serbia and monarchy actually won only 16% of votes).

Thus we reach the dawn of the war itself, which is another story. These were some of the deep causes that brought Yugoslavia to an edge of abyss in 1991. Other single events through '90 and '91 explain how Yugoslavia ended up jumping into that abyss. Those reasons are much more easily researchable on internet (to often never objective). If you want me to summarize that part too, please ask.