[davidivadavid]

I think the game design angle is the best here. What he's gesturing at, to me, is the concept of difficulty as encountered in games. You have to play at the highest level of difficulty you can tolerate without getting frustrated. If it's too easy, it's boring, and a sign you're not learning anything. If it's too difficult you give up. So it's not so much a binary thing as a matter of "right degree of difficulty"/balance.