The Treaty of Versailles came down on Germany and Austria like a trainload of bricks. They made them entirely responsible for the war debt... Everyone's. On BOTH sides. They robbed them of their national and cultural identity, sanctioned them all to hell, and sent them spiraling so far into abject poverty and economic depression that they would have followed Satan himself if he promised them any relief. They created a Hitler-shaped hole, and all that paper-hanging bastard had to do was step into it.
The funniest part is, Woodrow Wilson warned them that if they punished them too harshly, it would come back to bite them in the arse. His advice was ignored, and well.... It came back to bite us all, didn't it?