In which countries of Eastern Europe did citizens protest against the existing regime?

In which countries of Eastern Europe did citizens protest against the existing regime? What are the common reasons for the collapse of socialist regimes? Describe the current political development of Eastern Europe.

Citizens opposed existing regimes in states such as Romania, Poland, Czechoslovakia and Hungary. Socialist regimes inevitably collapsed, because the people initially did not accept the innovations, people did not show confidence in the new requirements. The regime was imposed by the Soviet Union, restricting the rights and freedoms of citizens. In addition, some of the above countries, for example Poland, had hostile relations with the Russian Empire, which was the legal successor of the Soviet Union.