Why were the relations between the USSR and Yugoslavia tense?

Since the end of 1947, external relations between the USSR and Yugoslavia, or rather between its leaders, Stalin and Tito, began to deteriorate. Firstly, it arose because of Tito’s too large foreign policy ambitions. For example, the statements of Yugoslavia in Trieste, attempts to encroach on the Austrian south of Carinthia, as well as the Greek part of Macedonia, propaganda of the decisive influence of Yugoslavia in Albania. Secondly, because Tito was an active person and wanted to achieve an independent policy, in contrast to the communist leaders who were eager to control the actions of friendly countries.