What caused the counter-revolutionary wave of 1989?
I know things were really bad in 1989, but what made it so bad that people in so many socialist countries just rose up and overthrew their own governments?
Not OP, but the dissolution of the ussr was entirely undemocratic. They also violated the constitution, which did have provisions for leaving, in order to do so.
That's a very vague way to say that a planned economy going down with USA doing actual humanitarian flights with actual food doesn't really help people to trust in any system.