If we use “I understand” and “I don’t understand” as one axis, and “get things done” and “cannot get things done” as another axis, we draw an interesting competence chart with four quadrants.
I don’t understand why you cannot get things done
This is lowest level. If I know how we can do it, but don’t understand why you cannot get things done, that is a series problem.
I can understand why you cannot get things done, or why you can get things done
These two are relative the same level – the two persons are of the same level – both can or cannot solve the problem.
I cannot understand why you get things done
This is the perfect situation. The other person is impressive. He/she can archive much more than what you can.