Interpretation is an important point. My music teacher discouraged interpretation of Mozart. I in turn refrained from discussing much about composition with the teacher and instead did that independently. She wasn't a bad teacher, but I don't think she liked me.
I am mostly a autodidact when it comes to music, but one who made it to some level (I play in a improvisational band). In my experience there are only few classical musicians who are able to work freely when interpreting a existing piece (and they are usually very good at what they are doing). But when you ask a regular classical trained musician to improvise, they will look at you in fear or start playing a piece they know by hard.
I think this is sad, because musician should be about fooling around and experimenting with sounds, melodies and phrases that come out of your instrument. Of course you can refine it all for a concert, but beeing a perfect classical musician should be more like Picasso and less like someone who tries to paint like a photograph (and keep in mind: Picasso was pretty good at the photorealistic stuff too if you look at early stuff). Music needs soul and that you only get through interpretation.
