Sometimes, even in effective, mass-consumer designs, it is useful to violate these principles. But if the user is to be effective at, these principles should be followed. There are several ways of getting a new user to understand what actions are possible. This was a major theme of POET, but there, the emphasis was on physical products, so perceived physical affordances were extremely important. Follow conventional usage, both in the choice of images and the allowable interactions.
Convention severely constrains creativity.
Following convention may also violate intellectual property laws. Sometimes we wish to introduce a new kind of action for which there are, as yet, no accepted conventions. On the whole, however, unless we follow the major conventions, we are doomed to fail. Those who violate conventions, even when they are convinced that their new method is superior, are doomed to fail. Words alone cannot solve the problem, for there still must be some way of knowing what action and where it is to be done.