I *love* them. Not that I listen to or play all of them at once, or any of them very often. They are incredible fun to read, and it seems to me they contain lots of jokes -- Russian Style, anyone?
Um, once about a hundred years ago, I complained about having to practice a Schumann piece, because I thought it was "dull". I was told "Dear, if you played it better, you would like it more." I learned to play it better and I like it more.
So , I guess I will have to play it better.
But wait a minute. In order to play it better I have to work on it. I find it unbearable to work on music I find dull, especially since I do not have that long to live and there are literally hundreds of thousands of pieces that thrill me to bits and are in the waiting list.
Hey, but wait a minute. There is a hole in your argument. I know what these pieces sound like when they are played better. You see, when I first sight-read through them, I thought: “How dull”. Hmmm… Maybe I am wrong and if I could just play them better they would sound much better. In all fairness this has happened before.
So I did what I always do. I bought, not one, but two CDs of Mikrokosmos played by two superlative pianists (one of which is arguably the best Bartok player alive). I listened to the full four hours of it. Several times. Over the years to see if my musical taste had improved. I still find them dull, dull, dull (with perhaps three or four exceptions within the 153 pieces).Maybe my problem is that I am not Eastern European, and have not been exposed to Eastern European Folk Music from childhood (as someone mentioned above), so this folk based pieces have no inner meaning for me (I was never that taken by the pedagogical material of the Russians either – Rebikov, Gretchaninov, Kabalevsky and so on – possibly for the same reason) while pedagogical material based on nursery rhymes I have been familiar with since childhood always has an appeal for me.
So, learn the 153 pieces of the Mikrokosmos? Nah, I am afraid I would rather learn the 555 Scarlatti sonatas.

Best wishes,
Bernhard.