Why was Truman angry leaving the potsdam conference?

President Harry S. Truman was angry after the Potsdam Conference primarily due to the disagreements with Soviet leader Joseph Stalin over post-war European policies and the future of Germany. Truman felt that Stalin was not adhering to the principles of democracy and self-determination, undermining the agreements made at previous conferences. Additionally, he was frustrated by the lack of progress on key issues, including reparations and the establishment of democratic governments in Eastern Europe, which foreshadowed rising tensions in the Cold War.