My impression is that Poland joined the EU in order to
The truth is far more complicated. There are civilization, cultural, economical, family, personal, sentimental, political, historical, military, etc. arguments pro and against EU. Different people could have separate opinions about each of them.
To describe it in the simple words: the most important thing is that foreigners absolutely do not realize how strong and deep divisions are in the Polish society. That is why they can not understand Polish policy, behaviour, etc. so often. Sometimes Poles tell jokes about two countries Pol and Ska here. As I wrote it is a simplification, but there is a part of "europeans" who have no problem with modern civilization values, acceptation of other cultures, minorities and Europe as a kind of big homeland. They are deeply attached to "our western" style of life, culture, values regardless of their age or material favours. Unfortunately you can't find them among this Polish sink managers or hopfer pickers you like to laugh at. The other group composes a strange zoo where the post-soviet style of live is blended with the catholic values, obsolete nationalism, xenophobia, soap-opera education level and pride of XII century victorias. Poles owe to them a lot of stupid stereotypes you can find on this forum too. There is a huge gap between this two mentioned societies. In fact they don't communicate each other. So when you are writing about for instance: "Polish attitude towards EU" you should choose first: Pol or Ish.