User friendly healthcare informatics system.

Why is it important that informatics systems be user friendly? In your encounters with informatics systems, have the systems been user friendly? Explain.
What does learnability refer to and what was your experience with learning this healthcare informatics system?
What does efficiency refer to and, in your experience, how did the healthcare informatics systems affect your efficiency?
What does memorability refer to and, in your experience, how easy was it to use the healthcare informatics system after being away from it?
Did you encounter any errors while using the healthcare informatics system? How can errors affect the usability of a healthcare informatics system?
What was your overall satisfaction with the healthcare informatics system?