The design goals should be based on commonly accepted design criteria. The problem is that each criterion may apply to our system, but the design goals based on these criteria may be inconsistent with each other.
Consider the two design criteria:
Assume that we have two solutions to the same design problem, one solution is fully automatic and the other requires user interaction. Suppose the automatic solution implies that the users need to wait about 10 seconds for the system to complete the processing, while the interactive solution takes about 20 seconds to complete. Research in interaction engineering suggest that typically users feel frustrated waiting 10 seconds for a system to finish its processing, but feel comfortable with the interactive solution, which takes 20 seconds to complete.
Updated on 13 Jun 2016.