Three great articles from Bruce Tognazzini (i.e. Tog) the founder of Apple’s Human Interface guidelines (HIG.) Back in the day Apple payed millions to figure out what exactly allowed a GUI to be useful and easily understandable… and they incorporated that knowledge into the old Mac OSes. Tog gives his opinion about the OSX Dock and Panther (the latest release of OSX.) For more information about human interface guidelines check out Fitts’ Law and Principles of Interaction Design (based on Fitts Law.)
If you think you are really knowledgeable concerning HIG you can take a Designed To Give Fitts test provided by Tog.
The final article is a discussion on quality assurance procedures called When Good Design => Bad Product. Its an absolutely wonderful synopsis of why good QA is fundamentally required for any level of application dependability.