Easy, Intuitive and Metaphor, and Other Meaningless Words
A vital skill for designers is to notice fine detail in the other designs which form part of the technological ecosystem in which their design will live. For example, on Mac OS there are now two different styles of text entry fields for forms. One has square corners, and is used for general data entry. The other has rounded ends, and is used for entering searches. I was recently outraged to find a piece of software which used the rounded style for data entry. This kind of design vandalism muddies the rules which users would otherwise learn, and devalues all software on the platform.
Bagnall, Peter. uiGarden (2007). Articles>User Interface>Human Computer Interaction