The mega milestone was the end of communism in the USSR and the USSR itself.
You seem to think USA and Soviet Union were equal partners in the end of 80s/start of 90s. They were not. US was at the peak of its power, both hard and soft. Soviet Union was a collapsing giant, bankrupt and hated not only by its official 'allies' from the Warsaw Pact, but also by significant percentage of its own population.
But I remember the poverty of the time, the lack of most basic necessities. And I also remember hope that inspired people when the regime finally collapsed and for the first time in decades Poles were once again in control of their own future.
Sure, the first years were difficult, we had to transform our whole economy and get rid of the rampant socialist wastefulness. And yet the program of socio-economic reforms had a firm support of the majority of population. Every government of Poland (including cabinets formed by post-communist politicians which lead the country in years 1993-97 and 2001-2005) continued with the transformation. Nobody wanted a return to the bad old days.
Of course, we also celebrated liberation from under Soviet control. When the last Russian troops left in 1993 we were finally free to pursue our own goals, which were quite evident to everyone: Poles always felt as members of the West, not the East, so applying for NATO and EU membership was a no-brainer. We knew Russian weakness is only temporary and were willing to secure our position in the structures of Euro-Atlantic partnership before it ends. And despite all the difficulties, we succeeded in this feat.
It's a pity our neighbours from Belarus and Ukraine could not take advantage of the same window of opportunity. If they did,we would not be having the conversation we have today.