Trop bon :
Design is basically problem solving under constraints: you must design a system that can actually be built, that’s within budget, and that works in the real world. Usability adds one more constraint: the system must be relatively easy for people to use. This constraint exists whether or not you include formal usability methods in your design process.
Human short-term memory holds only so many chunks of information. If you require users to remember too much, the design will be error-prone and hard to use because people will forget things when you overload their memory.
Also, if you’re designing a website, it will be one of millions available to users and they’ll grant you only so much of their attention before they move on.
These are facts of life. All usability does is to make them explicit so that you can account for them in your design. Usability guidelines tell you how people typically behave with similar designs. User testing tells you how people behave with your proposed design. You can pay attention to this data or ignore it; the real world remains the same regardless.
Knowing real-world facts increases creativity because it offers designers ideas about design improvement and inspires them to focus their energy on real problems.
Following design conventions doesn’t destroy creativity. Conventions and standards for interface design are like a dictionary for the English language: they define the meaning of interface units and offer guidelines for stringing them together. But the dictionary doesn’t define whether you’re writing Harry Potter, a Stephen King thriller, or an Alertbox column. Writing offers ample creative opportunity, despite the standard expectation that you’ll use language in ways that readers can understand. Interaction designers can be equally creative, despite a requirement that they design for the characteristics of homo sapiens.