Here’s my take on the Apollonian and Dionysian creative forces applied to interface design.
The Apollonian design force focuses on the content and the end goal. Here what matters is getting something done quickly and efficiently. Google’s spartan user interface design is a good example of this. The interface is there to help you do something, rather than to be experienced on its own. At the very extreme of this you have absolute function based interfaces where there’s no visual interface at all: the command line terminal. This interface completely internalizes the interaction between you and the computer, meaning that all of the thought process goes on in your head. You have to know what you want to do because there’s no visual guide to help you along.
The Dionysian on the other hand provides an experience, and so focuses on the interface itself as much as the content. Interfaces where experience matters tend to feature a lot of decorations that try to communicate a certain feeling, for example: video games and other consumer entertainment apps. Because these interfaces tend to be visually rich, they can be experienced on their own, independent of the content they’re designed to manage. Such interfaces externalize the interaction — the source of your experience no longer originates from your head but is instead coming from an external interface.
In the case of the Apollonian, your aim is to get things done, and so the interface can in most cases be considered as a barrier between you and the goal. Eliminating the barrier becomes the objective, and the interface that can get out of your way the fastest will be the most successful. In the case of the Dionysian, the user is actively looking for you to provide an experience — and so interface becomes part of the end goal. In this case the interface that looks the best and evokes the right feeling will succeed.
The above assumes that the users of the interface completely fit the profile. This is never the case, which is why we often hear complaints of either too much or too little eye candy, too steep or too shallow learning curves, and so on. Of course people never ask for more eye candy, they usually just call the interface ugly, even if it does the job. On the other hand we also have people who can’t stand the visuals, craving the clarity and efficiency of the command line. It’s not that these people don’t like visuals, it’s just that what they want to do with the computer doesn’t involve them.
What’s more interesting — and this is from my own experience — is that the stance towards one or the other type of interface will vary depending on the use case, even when using the same product. For example, when I need to get things done I would cease caring for how good the Mac OS looks — I would just want it to get a certain task done. Later when I’m relaxing it’s the opposite: I enjoy those very same visuals I didn’t care about hours earlier. Some apps have the advantage of lying on one or the other extreme, e.g. the command line or the computer game interface. Others have to play the hybrid and try to juggle both use cases, e.g. the operating system.