Relevant to your insight (see "The Design of Everyday Things" by Don Norman): 1. The gulf of execution: how do I do something? (i.e. what can be clicked/tapped

Relevant to your insight (see "The Design of Everyday Things" by Don Norman): 1. The gulf of execution: how do I do something? (i.e. what can be clicked/tapped/pressed?) 2. The gulf of evaluation: how do I know/understand what happened as a result (of clicking/tapping/pressing something?)