Final answer:
Italy had the most negative experience at the Paris Peace Conference as their expectations for territorial gains in Dalmatia, promised for joining the Allies, were unmet due to President Wilson's opposition, leading to discontent and anti-American sentiment in Italy.
Step-by-step explanation:
Most Negative Experience at the Paris Peace Conference
The nation that had the most negative experience at the Paris Peace Conference was Italy. During the negotiations, Italy was promised territory in Dalmatia in return for joining the Allied cause according to an agreement made in 1915. However, President Woodrow Wilson opposed the transfer of this territory to Italy, leading to Italy being forced to relinquish its claims. This resulted in significant discontent and anti-American rallies in Italy. Representing Italy at the conference were the Prime Minister Vittorio Emanuele Orlando and the foreign minister, who were both part of the discussions, alongside leaders from Great Britain, France, and the United States. The dissatisfaction felt by Italy placed it in contrast with the experiences of the other major allied nations present.
While France and Great Britain sought reparations and territorial gains, Italy's expectations were left unmet, making their experience at the conference particularly disappointing. Moreover, internal ethnic issues in Europe, such as those in the creation of Czechoslovakia, remained unresolved and posed potential future conflicts, further contributing to the sense of a negative outcome from the perspective of Italian interests.