Tom Waits is not only a talented song writer and performer, he also provides some of the greatest insights in to creativity and the creative process through his discussions on song writing.
This is hopefully the first of a series of memorable quotes on the topic.
The Guardian published It's perfect Madness where wait's discusses his 20 most cherished albums of all time.
On discussing 'Solo Monk' by Thelonious Monk (no. 3 in his top 20) he comments:
"... there is a certain veneer to jazz and to any music, after a while it gets traffic rules, and the music takes a backseat to the rules. It's like aerial photography, telling you that this is how we do it. That happens in folk music too. Try playing with a bluegrass group and introducing new ideas. Forget about it. They look at you like you're a communist."
I don't know about the communist bit, but I can think of plenty of situations where a particular discipline or group defines themselves by a rigid set of rules.
Update: There's an overspill piece with a further 9 songs that weren't included in the article.