Another Polish here: truth is, whether we have a single currency or not doesn't matter as much as people think it does. For most people, it's about symbolism, not about practical economic consequences. I guarantee you that average person has no clue what it really means for the economy to adopt euro. BTW the argument "let's wait for our economy to catch up with Germany" is just deceitful because there will always be differences between economies. Imagine arguing that Nebraska shouldn't be using the dollar until its economy catches up with California... which is going to happen "not in my lifetime".

I am strongly pro-euro. Why? Because again, economic consequences are way smaller than most people think, and it's about symbolism. It's about slowly marching towards European Federation instead of NIMBYism that prevents EU from actually living up to its full potential. Imagine a world where the entire European continent is a single political entity - we'd be unquestionable superpower. But no, because "muh independence", and the end result is that we can't do shit on the international stage because we're too busy arguing with each other.