As Communist countries go — which is not very far at all — post-1945 Yugoslavia had been a moderate success. True, living standards were mostly pitiful compared to western Europe. And there was a secret police — UDBA — that monitored dissent; ran a ferocious prison island; and assassinated opponents who had fled to foreign countries.
But most people did not live in perpetual fear of the authorities; within limits, different opinions could be expressed; and one could mingle with visiting tourists, travel abroad freely, and read foreign publications.
And yet the fact remained that Yugoslavia was held together mostly by force. Its peoples had stumbled into one state by accident of the world wars. No matter how hard Tito and the Communists worked to generate a sense of cohesion, the results were limited by ethnic resentments which, though they falsely claimed to be almost eternal, were actually the product of recent generations — and that was actually just as bad.
By 1990, with Tito long dead, Communism in freefall, and 'democracy' beckoning, the centre could not hold: things fell apart.