I also very much recommend all the comments under the video! (which happens rarely)I was incredibly intrigued by all the commentaries under this video, so I feel obliged to add one of my own:
I am Czech, but I think I truly discovered Suk and his music only today with this Scherzo! (although I was brought here already by being intrigued a lot by his op. 26 Praga) The most interesting discovery for me was that probably all commentators here are from abroad (or perhaps the Czech commentators hide under different uploads of this composition with a Czech name "Fantastické Scherzo" - hard to say) but it may be that Suk was indeed an underrated composer even most Czechs have problems recognizing (at least the non-musicologists, just casual listeners of classical music), outshined by Dvorak just like (as one commentator mentioned) Salieri was outshined by Mozart - or even Mozart's own father, a brliant composer himself Leopold Mozart, completely and utterly outshined by his own son!
Many commentators here mentioned a folk Czech theme in this song, however, as a Czech, I don't recognize that folk theme - either it is too local or too obscure (or both). Anyway, I wanted to provide our international friends with more information, so I searched all over the Czech Internet for more information on Suk and particularly this Scherzo, I found out one very comprehensive (50 pages long) dissertation work (@2017) by a student of musicology just about this scherzo alone! He tells you the first and the last thing about how this Scherzo is made, why, what it could mean and everything else, but nowhere I find a reference to a Czech folk song either... It may be that it is indeed obscure, but by now, I believe that everything you hear, no matter where the inspiration could have been from, is mostly a novel invention by Suk himself.
What I found out with many compositions of Suk (it certainly was true for me with his Praga, and it is ten times more true with this one) that, when I hear the composition for the first time, I am slightly intrigued but not thrilled neither I am offended by the music in any shape or form. When I hear the composition for the second time, I'm becoming strongly intrigued but not yet very thrilled - but I'm desiring to hear it at least one more time again. When I hear it for the third time, I'm becoming deeply moved, thrilled, enchanted, fallen in love. And with every other listening I am more and more desperately lost in the beauty of the music. Just today, as I was reading the dissertation work I talked about earlier, I must have played this song at least 30 times! ... and I haven't satisfied my hunger yet!