In addition to composing music myself, I also know several composers. Most (including myself) appear to be introverts, but some are extroverted. One quality I’ve noticed is the differing nature of the music composed by the introverts and extroverts, as well as the ideological differences as to what music is:

Introverts appear to write music primarily concerned with emotion, thought, and reflection. They appear more likely to view music as a crystallization or actualization of emotion or some other internal state. The music itself even appears to be introverted, and can be described with terms such as warm, reflective, expressive, tormented, serene, tranquil, or haunting.

Extroverts, on the other hand, appear to write music in response to exogenous stimuli. They are more likely to compose music that evokes past experiences, and will usually cite a desire to return to the state of mind that such experiences placed them in as the motivation behind their music. Words that may be used to describe their music include evocative, motive, energetic, playful, smooth, clean, or humorous.

That’s not to say that either are “better”; they aren’t. They’re just two sides of the same human coin.