Unstable borders
The creation of new Nation-States ended four empires and the power of the German, Russian, Austro-Hungarian, and Ottoman royal families. Splitting these empires created large mobility problems. The existing roads and railways didn't serve the new nations as they were built for the old empires.
National Minorities
There are many different cultural and ethnic groups that exist in continental Europe. It was impossible to give each group "self-determination" and create their own nation. Instead, most of the new nations contained dissatisfied minorities whose cultural groups had been split by arbitrary (random) borders. Large numbers of people found themselves in countries where they were suddenly a minority e.g.; millions of Russians now lived in Poland, Germans now living in Austria, etc.
Economics
Old empires lost large amounts of working people (e.g.; Austria lost 40% of its population and two-thirds of its territory), while simultaneously losing resources and being made to pay reparations. Furthermore, trade was now taxed between nations that had previously had free trade.
Resentment
The central powers had huge anger towards the allies and the cultural and economic situation they had been forced into because of the treaties. In 1919, Hungary’s communist government was replaced by a military dictatorship, and Germany’s royal family was replaced by a democratic republican government (Weimar Republic).
Germany saw the terms of the treaty as incredibly unfair and felt that it was forced, labeling it a "slave treaty" or "Diktat" (forced treaty). They believed that it was undignified and that a great power like Germany was unworthy of such a Treaty.
The Allied Powers maintained a military blockade and threatened to take further military action unless Germany signed the Treaty of Versailles. The threat of increased food shortages and economic issues forced Germany into signing. Thus the term "diktat" (forced treaty).
The treaty was very different from Woodrow Wilson's 14 points. It didn't follow any of the principles set out and was far too harsh in separating areas and people that were considered "German".
The War Guilt clause forced Germany to accept that they were solely at fault for a global war. The Germans firmly believed that they had fought for defensive reasons due to potential encirclement from the Allies.
Britain and France remained heavily armed, which created fears for safety.
Truthfully the treaty was a compromise that could have been far harsher, however, the terms sowed discontent amongst the German people, which created the "Stab in the Back Myth". Hitler later used this to alienate the Jewish People (World Jewish Conspiracy).
This second activity is source analysis, which you should all be familiar with.
Make a table of the Values and Limitations of the 2 sources below.