I'm sure that the way much C20th "national" music is very largely based on regional speech rhythms and patterns has a lot to do with one's appreciation. I personally feel very comfortable and at home with what might loosely be called North European (and North American) music; whereas while I can well appreciate the obvious merits of East Europeans such as Janaceck and Bartok, I can manage no more than objective admiration - the music doesn't "speak" to me in anything like the same way; and over the course of prolonged exposure to Janacek's operas I've come to the conclusion that I find the pattern of short, choppy, fragmented phrasing - clearly based on Czech speech rhythms - alien, and actively off-putting; whereas I always felt at home from the start with the longer, more liquid flow of a composer such as Atterberg, clearly echoing the lyrical rise and fall of spoken Swedish. My loss, I'm sure (as I'm always being told) but it isn't like there isn't plenty of other music to explore...