...And then after you've mastered it and can play it flawlessly, it's just not as exciting...
Although what Rach3 says is true in certain cases, there is another possibility. The piece was not that fantastic to start with. There are some pretty poor compositions out there that are impressive on first listening (e.g. Fur Elise, Fantasie Impromptu) that soon outstay their welcome. Truly excellent pieces (e.g. WTC) can usually be played for a lifetime (and usually a lifetime is not enough). As ones’ musical judgement gets better, this (getting bored with a piece of music) happens less and less because one tends to concentrate on the superior (musically) repertory.
Although what Rach3 says is true in certain cases, there is another possibility. The piece was not that fantastic to start with. There are some pretty poor compositions out there that are impressive on first listening (e.g. Fur Elise, Fantasie Impromptu) that soon outstay their welcome. Truly excellent pieces (e.g. WTC) can usually be played for a lifetime (and usually a lifetime is not enough). As ones’ musical judgement gets better, this (getting bored with a piece of music) happens less and less because one tends to concentrate on the superior (musically) repertory.Best wishes,Bernhard.
I particularly agree with the WTC comment - some works by Bach are truly timeless.
Also: I'm not sure wether I should use "epokes" or "styles" or something else covering baroque, romantic, etc. (I don't know the english naming...)