Many people view GUI(HMI) design as the cosmetic aspect of the underlying Engineering products or problems; other people view this a serious engineering topic as part of the products/problems.

In a highly competitive business world where quality and customer satisfaction is ultimately emphasized, software is more appropriately addressed as service rather than product. Thus, software usability depends on both the 'quality' in a traditional sense, but also customer experience. However, very often than not, we are seeing people/company creating/upgrading products which prevent people from using it or loving it (you hate it, yet, you may still have to use it, :( ).

As a very intensive sofware user, observer, I wish to compile a check list as warning for all GUI engineers, including myself.

1) do not use out-dated technologies for the sake of compatibility; be a hero, lead the revolution! we should avoid creating software which we know will only survive a few months.

2) do not count on users to read and comprehand your thick mauals! let your software speak for itself. Use their language and sign, follow their thinking, and mimic their habits.

3) do not let user repetitively input information. And, you know what I am talking about. That is NOT called validation or security measure, it is called 'amnesia'. Always remember what the user has told you until they have logged out or timed out.

4) be intelligent. Try to make use of known information on the fly, and avoid asking stupid questions. (we do not ask NRIC number from a foreigner.)

5) always leave your user a choice. Customer is god! your god should be able to do whatever whenever they want. They should be able to quit, delete, save, roll back, un-subscribe, un-focus, etc anytime on any page.

6) allow user to copy n paste, including pictures and objects.

7) consider i18n, if you can not support it, at least do not let it ruin the running instance of your program. (There are many such cases in the web: when you switch the input method, the page hangs or browser suicides.)

8) consider error handling. that is one of the basics in software engineering. Testing cases are part of error handling design.)

9) do not display useless information. Exception stacks are only useful to programmers, do not let them run out of the curtain, and that just adds to the frustration over the awkward accident. if it is going to die inevitably, let it die silently and rest in peace.

*) last but not least, never assume your software is perfect. the most we can achieve is 99.9, and 100 is hallucination. Consider debugging and error logging devices seriously ever since the design stage. Software which does not allow debugging and error logging can hardly achieve a passing grade.