Something that puzzles me to no end is the fact that people seem to have extreme problems defining and categorizing music, when music, by its very nature, consists only of elements that are precisely and carefully defined so that they can be exactly reproduced.

Notes, melody, chords, rhythm, measures, all can be marked out exactly, and often are. Every element can be documented, precisely recreated, and even taught so that others can precisely recreate it--so why all the vagueness and ambiguity?