If they didn't sign it they threatened to send the Allies to invade their country. The Germans felt this was rude because they didn't think the cause of the war was just their fault.
So they got screwed over pretty badly along with being badly in debt (especially to France).
- They lost colonies to other countries.
- Their military army shrunk to 100,000 men, no air force and only 6 battleships.
- They weren't allowed to join with german speaking Austria.
- They had to pay off a lot of debt (later fixed at £6600million), this included paying off with goods, such as letting the French mine coal in the Saarland.
- They weren't allowed to station troops in the Rhineland either.
Basically after WW1 no one liked them and they all decided to pick on them and make them pay for the war, even though they had no money.
France, Belgian, America, Britian, Italy....: hahhhhahahahahahhahahahhahahahhahahahahahhahaha.
The treaty set certain requirements that Germany had to agree on and accomplish which were completely unfair to Germany but made sure Germany had no real choice but to agree. Germany got fucked over.
Everyone: haha your so fucked!