The terms of treaty of Versailles such as reparations, war guilt, disarmament, and loss of German territory made German anger and cause German to hatred towards against the allies. The allies done several things to keep peace such as setting up League of Nations, the Dawes plan, the Locarno Pact and the Kellogg-Briand Pact during 1920-1929.
The first reason which made Germany anger was disarmament. The allies told Germany to reduce number of army to hundred thousand soldiers and forbidden to have tank. They told Germany to have small navy with six battleships and no submarines. Also, any kind of air force was not permitted. This was because France was worried that Germany ignores the Treaty of Versailles and attack France again.
The second reason which made German anger was reparations. After the world war one, the allies such as France and Great Britain told Germany to pay war debts or reparations of 6.6million pond to cover some of the costs of the war which was impossible for Germany at that time. The Germans thought and complained that the allies were trying to bankrupt Germany by making high amount of reparation claims. The reason that the allies tried to make Germany to pay huge amount of reparations which was unable to offer was also because France wanted to keep Germany weak by making heavy reparation. By making Germany to pay huge amount of reparation, France tried to avoid German's to rearm again and attack France.
The third reason was loss of her territory. In Treaty of Versailles, it says that Germany has to give 13 and half percent of her territory, with seven million people, to neighbour countries. German loss includes the loss of Alsace and Lorraine to France, loss of land to Belgium and Denmark and they had to create Poland by losing her territory which made East Prussia to split away from the rest of Germany.
The fourth reason was the war guilt.