what is good music?

I can't define it, but I know it when I hear it.

With respect and credit to Potter Stewart.

I find "good" is not the right word. By your definition something like Schnittke's 2nd violin sonata would be "bad" music, which this piece is anything but. It is highly dissonant, highly atonal ( though it is not readily serially atonal), there is no melody. In fact near the end,
the accompanying piano strucks in the C major key, the basic C chord in all its glory and loud. Wow! Here is the most basic of basic stuff, and it was so out of place! Probably the most gratifying concert I have ever been to yet the piece played would hardly be called "good". So it is more of the aesthetics of music as art, that determines whether the piece is "good" or "bad".

In the world of Adorno, the dialectical master of musical aesthetics, the commercial side of music, he deemed corruptible and not worthy of being considered, it was all "bad". However I take a different take on commercial music, it is just a form of entertainment, just like TV or football, whether it is the Beatles or Nirvana or James Brown or any rap group, its only entertainment in the form of music. So enjoy it and relax, and as the Stones' said..."it's only rock and roll!"

I've actually sat here for 15 minutes wondering "what is good music" and I really have no idea.
I do like chicken wings...............I'm hungry.

Classical music is filled with examples of pieces that were not received well upon first hearing, heck for several years in some cases ... so I don't think initial listener reaction is a good guage of worth or value. I'm sure many of us have had the experience of having an album grow on us. Often it takes time to understand/appreciate the structure and logic of expression.

What you enjoy.