Anti-ex. or repeatedly push the pedestrian button at a street crossing? => Because user doesn't know whether system got his request or not.
Feedback—communicating the results of an action—is a well-known concept from the science of control and information theory.
You can't hit a ball without seeing the target
You can't pick up a glass with hand without the feedback.
Feedback must be immediate: even a delay of a tenth of a second can be disconcerting. If the delay is too long, people often give up, going off to do other activities.
It wastes resource to do one thing that user doesn't wait for it anymore.
Too much feedback become annoying.
Ex. When performance tuning, we need major number to alarm. It will be useless if we alarm everything
Backseat driver: too much feedback to driver. May distract people or just turn it off
Use one simple signal producer to reduce cost, let people not easy to remember (Beep code)
Beep code definition may be different in different machines. We'll be confused when those machines beep together.
Feedback has to be planned and prioritized.
Feedback is essential, but it has to be done correctly. Appropriately.
