@The Pentacle Queen,
I think I agree with that.
Music can be both an expression and an impression of emotion. The thing I like about it is that you can use music to express emotion without expressing what the emotion is about.
If I play an aggressive riff on my guitar, I might be expressing irritation that has accumulated during the day, say while driving home during rush hour. A person listening might have accumulated his irritation during the day by sitting in a warm office where the AC was down.
By playing I work through my irritation, and by listening he works through his. If we tried to do it by means of a conversation it would perhaps not work. He might think I was foolish to complain about sitting in a car, where I could have had the windows open, while he sat in his office sweating, and I could just as easily fail to relate to his irritation because sitting in an office would seem a lot more appealing to me than enduring the stress of rush hour.