Breaking the Rules

I enjoy an apt quote. I'm also intrigued by the nature of how our brains work. Have you ever noticed when working in a particular topic area that certain quotes stand out which might otherwise be uninteresting? This happened to me while defining a set of best practices (rules, guidelines) for a project. While doing so, I was also reading Tim Hurson's Think Better: An Innovator's Guide to Productive Thinking where he summarizes his "productive thinking" method as follows:

"As in any discipline, to become good, you need to first learn the rules. To become great, you need to break them."

He follows up with a Chinese quote (he did not happen to say proverb, which I found somehow interesting):

"Not to have a method is bad; to stop entirely at method is worse still."

So, first we need to understand the rules; then we become great by learning when it's appropriate to break them.

Questions: Do you think to be truly great you must break a few rules? Are there rules you are unwilling to break? Does it help to think of the set of rules as a box, following rules as staying within the box, and breaking rules as "thinking outside the box"?