Austria-Hungary was a tumour and it collapsing is one of the only arguably good things to come out of WW1.
I've no intention of getting involved in the debate on the merits (or otherwise) of Austria-Hungary, but I will take issue with the second clause.
Some good things did emerge from what was generally not a good time.
There were significant advances in Medicine. The fact that there were so many wounded gave medical practitioners plenty of practice, and numerous techniques were developed. How to treat burns, for example, came on a long, long way.
On the social front, it brought about a lowering of the class barriers by a significant amount. MacMillan, for example, (later to be PM of Britain) remarked that prior to the war, he'd had no occasion to interact with the "working class". However, while he was in the trenches, he came to see them as people, with hopes and fears and emotions and all the rest, whereas previously, he'd regarded them as somewhere between "real people" and "working animals". That revelation informed his politics. In memoir after memoir - British, French, German - similar discoveries are made with the enforced intermingling of social classes, transforming the perceptions between them.
It also brought about a significant change in women's rights. Not just the vote, but in the recognition that they could do useful work. Medical schools became more open to accepting women to study to become doctors (previously, it had been - difficult).
In some countries (UK I know for sure - I can't speak for others), the link between unhygienic conditions and poor health was demonstrated, leading to attempts to create more hygienic conditions for those living in squalor.
In France, antisemitism took a big hit; Jews volunteered in large numbers, specifically requesting to be assigned to the Infantry - the most dangerous posting - to prove their loyalty to France. This was noticed, and the sentiment that had been around pre-war (see the Dreyfus affair and fall-out from same) that Jews weren't loyal to France was laid to rest. For a time, anyway. It rose again after a couple of decades, peaking with Vichy France. But, for a couple of decades, antisemitism had taken a knock.
Me. I'm a direct consequence of WWI. My four grandparents all came to London precisely because of the war: (from Ireland as a soldier, and ending up settling in London post war; from the far north to work in a factory in London; from Sicily by volunteering for the RN because there was no way he was going to fight for Italy but wasn't going to be called a coward, and unvolunteering in London when the war was over; and from Jamaica, as a trained nurse). Without WWI, none of them meet. So, me.
Actually, there would be those that would say that my existence is not a good thing, but I pay them no heed.