Three reasons why relations between the US and Cuba worsened are:
1.) The Cuban Revolution: The Cuban Revolution led by Fidel Castro in 1959 overthrew the US-backed dictator, Fulgencio Batista, and established a socialist government in Cuba. The US government, which had previously supported Batista, saw the socialist government in Cuba as a threat to its own interests and began to implement policies to isolate Cuba economically and politically.
2.) Nationalization of US-owned properties: After the Cuban Revolution, the new government nationalized many US-owned properties and businesses in Cuba. This included sugar plantations, oil refineries, and other valuable assets. The US saw this as a violation of its property rights and responded with economic sanctions against Cuba.
3.) Bay of Pigs invasion: In 1961, the US sponsored a failed invasion of Cuba by Cuban exiles known as the Bay of Pigs. The invasion was an attempt to overthrow the new Cuban government and install a US-friendly regime. The failure of the invasion further worsened relations between the US and Cuba.
These reasons made the US hostile to Cuba because the US saw Cuba as a threat to its interests in the region. The US was concerned about the spread of socialism in the Western Hemisphere, and saw the Cuban Revolution as an example that could inspire similar revolutions in other countries. Additionally, the US was concerned about losing its economic and political influence in Cuba, which had long been considered its backyard. The nationalization of US-owned properties and businesses in Cuba threatened US economic interests, and the failed Bay of Pigs invasion was seen as a blow to US prestige and credibility. As a result, the US responded with a policy of economic and political isolation of Cuba, which has persisted for decades.