Concrete to the Abstract: adapting what is fun to larger concepts

These consultants (like all of us) are having a difficult time understanding *what* specifically makes a game fun. I am working with them to help them understand some of these ideas. For example, one said that Donkey Konga was fun because you could keep beating to the music and it would get faster. I'm struggling to figure out how to help him recognize that this is one way of creating challenge. I may work on another approach where I give them concepts (Challenge, Flow, Interface Use) and have them give some examples... I don't know if moving from concrete to abstract is something that gets better with age, or with exposure and learning. We'll see.