There's great enjoyment in letting all our emotions release in music. The reason why rock music continues to thrive to this day is due to the emotional excitement not seen in other genres.
Bands that do this well (my favorites being Soundgarden, Pearl Jam, Black Sabbath, and Rush) keep me pumped and motivated for my next project.
Composing for rock uses different music mental muscles than orchestral composing. That's why I love to alternative writing between the two.