for starters:

machinistic contemporary long hair music where the instruments are forced to scream, gurgle, scurry, blat or overblow. No melody is allowed. I call this stuff 'ink ank oink.'

Any music where the chord symbols have more than one feature after the chord name. D7 is okay. D7sus4 is not.

Any vocal music (such as a John Rutter alto part) which a musical person has to practice 40 times before mastering.

Any instrument which costs more than an average home. Pipe organ comes to mind.

Sorry, but I won't be around for a while to hear the cheers and huzzahs which are sure to greet this breakthrough. (yeah right)