The system should treat all user input as sacred.
Users do not care about what is inside the box, as long as the box does what they need done.
A well-designed and humane interface does not have to be split into beginner and expert subsystems.
What users want is convenience and results.
Right now, computers, which are supposed to be our servant, are oppressing us.
As far as the customer is concerned, the interface is the product.