It is fascinating for me to watch and I wonder if the differences between Polish and Czech are comparable with the differences between German and Dutch, German and English, English and Dutch, Frisian and Dutch, Swiss German and Dutch, or if it is more like the large differences between for instance the West Germanic Dutch and the North Germanic Danish? To me the differences between slavic languages seem to be larger than between the West-Germanic languages, because for instance Frisian, Dutch and English are very close to each other and German and Dutch are extremely close to each other and yet different.
Whenever I hear slavic languages I often first hear the Slavic general nature (as a non-Slavic speaker) and secondly hear the specific slavic language without exactly knowing which lanuage it is. Only Polish and Russian for me are clearly distinguishable. Czech, Slovak, Sorbian, Kashubian, Silesian, Goral languare, Ruthenian (Wendish), Serb, Croat, Bosnian, Montenerganian, Slovenian, Macedonian and Bulgarian are for me hard to distinguish, because I didn't heard and hear these language often. Ofcourse I heard Polish and Russian more. Polish in the sense of family, some Polish friends, Polish cinema, documentaries with subtitles, the fact that there are Polish guestworkers here whom you hear speaking Polish on the street and ofcourse these Polish Culture Forums. Russian I hear because I like Russian music, Russian poetry, Russian music and Russian culture in general. Not the Russian politics and politicians.