The author states that a product must have discoverability and allowing understanding to be usable, without these it would not be human-centered enough and cause fustration. Except for all the example mentioned like doors and remote controls, one that often bothers me is the shower knobs at hotels. Usually we assume twisting a knob to the left is hot water and to the right cold water. I have encontered ones that are the opposite, ones that control temprature and water flow at the same time (it definately isn’t a water pressure problem it is a true design flaw) , ones that need a button to be pressed before it is spinned, and other confusing designd. This lead to me standing before the shower head for at least half a minute every time tryin to figure out how things work, and often getting blasted by cold water accidentaly.
The same applies to a lot of electric cars, at least my experience back in China was sometimes frustrating. The electric cars almost all aim for a futuristic design, many following Tesla in using the flat door handles. Some of them need to be pressed to pop out, some of them requires the driver to control them, some are automatic and some need to be pressed on one side, grabbed and them pulled to open the door. The open door button inside the doors and easily just as annoying as them come in knobs, buttons and handles.
The authors idea that the design should be human centered can serve as a central rule to interactive design. The experience of the participant is of the utmost importance. For example, signifiers should be present almost everywhere. The interaction is most likly strange to the user, so they must be instructed what to do. Clear instructions would make an experience a whole lot better than a confusing one.
Feedback is also a key component. Feedback should be fast and accurate to the action to allow the user to truly feel that they are engaging in an interactive activity. It needs to be clear to what it is responding to create logical connections between the users actions and the design’s response, creating a smooth transition in interaction.