Out of the Box Vs Established rules?

Now this is a tough one. There is, well for me anyway, this very strong feeling to want to rebel and break with tradition. Who says you can't? Why do you have to follow rules? Well I have learnt the hard way that sometimes following the rules can work, especially when the rules are supported by cold hard facts. There are examples of this throughout most areas of design. An example of this is white copy on a black background. Lots of folks like this, yet focus groups that were conducted on the matter show that most people find it difficult to read adverts that are designed in this way. So the next time you get the urge to break a rule its worthwhile to find out why the rule exists...