This reading was both very illuminating and validating, especially in regards to the initial discussion of confusing doors. I had always found UI design to be an interesting topic, and this glimpse into the field of design as a whole was a lot more involved than I was prepared for. I was definitely impressed by how much work goes into properly designing a product, only for the bestowed ease-of-use resulting in users remaining completely oblivious to the effort put in. In that sense, it is similar to how good audio mixing in a song or film will go unnoticed, but bad audio will completely pull you out of the experience. There were also some good points made later on about having to carefully balance the different aspects of design, such as signals and feedback being informative yet unobtrusive, or products being feature-rich while remaining affordable.
As for applying these design principles to interactive media, I am at a bit of a loss. In the past few weeks I have experimented with using simple forms of interactivity like clicking or using arrow keys to move an object in the p5.js scene. These ended up being fairly intuitive in the sense that they are reasonable choices that one would expect when using a computer. However, if the user was not aware that these pieces were interactive to begin with, a huge chunk of the experience is lost. I had left comments at the top of the code detailing the viable inputs, but of course this requires navigating from the WordPress site to the p5.js editor. A straightforward way to deal with this would be to include text instructions in the piece itself, or having some sort of help menu, but I still feel like this would negatively impact the more artistic pieces.