The EU to me is about brain draining the poorer countries for their own gain...
Czech (verbally) isn't very similar to Polish. There's a few words, but the words sound very different - if I had to approximate it, Czech to me sounds like an American trying to speak Polish - it's missing a lot of the weird sounds Polish has. Written CZ is a different story, I can read most of it.
Polish is closest to Slovakian and Ukrainian. CZ is different enough that I usually have to use English there, whereas in SK I can use Polish (including in more complicated situations where I had to stop at a car dealership to explain that I need to buy a very specific type of motor oil).
Edit: Just remembered another reason why CZ is so hard for me.
Polish: "szukam was na zachodzie" = "I am looking for you in the west"
Czech: "?ukám vás na záchodě" = "I'll fuck you in the toilet"
Both are pronounced the same. You can see how this could lead to misunderstandings
