"Ever watch people at an elevator repeatedly push the Up button, or repeatedly push the pedestrian button at a street crossing?
Ever drive to a traffic intersection and wait an inordinate amount of time for the signals to change, wondering all the time whether the detection circuits noticed your vehicle (a common problem with bicycles)?
What is missing in all these cases is Feedback: some way of letting you know that the system is working on your request," Don Norman explains in his masterpiece "The Design of Everyday Things" (originally published in 1988).
Feedback is described as one of the 7 fundamental design principles of design by Don Norman, and, as you can see in the video below (if on mobile tap to expand), applies to all products out there.
Originally posted on Linkedin: linkedin.com/feed/update/urn:li:activity:6490618372399591424
Ref: "The Design of Everyday Things" ⇢ https://amzn.to/2Ckjys4