I've been trying to ascertain whether or not the Average Joe actually even notices this kind of thing, but I am coming to the belief that in fact yes, they do....and of course I'm talking about integration among different applications on their system. Whilst at work, I get to see a lot of third party Mac apps as well as official Mac apps, and I started taking note of how well the design and the functionality integrated both back to the base system as well as to each other.So..what did I just say? Well let's break it down:APIIf a GUI framework has a strong set of API's for programmers, the programmers will use them. If the API's reach enough of a high-level function, they will greatly add to the sense of consistency on that platform. For instance, the Mac TEXT palette and the COLOR PICKER are both obviously cocoa API's that every programmer can use in their app. And because of this, any time a user looks to pick a font or a color, they always get the same exact dialogue box.BUTTON LOCATIONSThs is the great ideal that no one ever reaches, but the idea is that an OK button or a CANCEL button or whatever, will always be in roughly the same place. Or a BOOKMARKS button or HOME button or whatever.