If a chart follow all the “rules”, is it a good one? Not necessarily. What is way more important for a chart to be GOOD is to be aware of and serving well the context. Charts are just a form of Communication, and any good communications need to be easily understood and well received by the audience. The ultimate goal is to be understood, not to stick to the rule book. (Obviously, rules and conventions are still super important as they provide the general guidance which would be good in many cases).