To pull a quote from the article Sorce linked:
"However, it should be noted that it would never be possible for every facet of a tree to comply with the Golden Section, neither would it be beneficial to try to. Trees, trunks and branches do not grow in accordance with an Artistic Law and its over use within a composition could well become too visually repetitive."
IOW, it is a design principle to keep in mind, not a "rule" at all really. There are not any RULES in Bonsai or most any art for that matter... There are suggestions out there, and tendencies that are aesthetically pleasing. Bonsai is a horticultural endeavor first and foremost, because you must KEEP THE TREE ALIVE. That is the only TRUE RULE. All the style guidelines are there to help you get started styling a tree or to perhaps help you work through a difficult piece of material. If you have a tree where you cannot find the Bonsai in it for instance... You can always begin by removing the branches you know you probably won't need- the twigs pointing straight down or crossing each other in an ugly way... The branches that grow directly across from each other- chose one to keep or remove both if in a bad spot... Use the "rules" to get you a tarted, clean it up a bit and before you know it you will sometimes start to see the tree within that you were missing before! They can be a launching pad, a direction... But please don't ever think of any of these design suggestions as "hard and fast rules".
I am with you on this. A good portion of Art is actually intuition. Some people have to get the yard stick out to measure 38-62, other can just plop it down and it's perfect. But art is also about being understood. If it is pleasing to you, but no one else understands, then by failing to convey your intention to the viewer, the piece fails. I love Andy Rutledge's example:
"Self-expression
Bonsai is defined in all kinds of ways by all kinds of people. One popular and effective definition of bonsai is as a means of self-expression. Your individual working concept of bonsai will drive your bonsai stylings and surely your own particular idiom will embody your artistic attempts. But if you are ignoring the conventions of artistry, your work will come up short in its ability to communicate with those who see it — other than yourself. Self-expression is impotent and largely irrelevant without a common reference for conceptualizing your communication.
A silly example
Imagine meeting a gentleman at a party one evening. You say “hello,” and he responds with an ear-splitting “PEEYOW!” Shocked, you ask if he is okay.“PEEYOW!” is his response. At this point you politely excuse yourself and go find others to talk to. Yikes!
Now, this person is just happy and he uses PEEYOW! as his preferred means of expressing this happiness. However, there is no common reference for just anybody to be able to grasp the meaning. So, his expression is wholly irrelevant to those he meets.
Now, it is a common convention for happiness to be expressed by an exclamation of some kind, but that exclamation is usually formed within the context of a commonly understood convention, like the vocabulary of the relevant language (or the contextual understanding that the guy does not speak English). Further, exclamations of happiness are usually bound within the context of social norms. In other words, communication is largely bound by basic conventions; widely recognized norms that are readily understood by just about everybody."
Thanks.