The sweet spot for flow and mastery where the task is not too easy, not too hard — it’s just right.
Also, just the right spot for learning similar to Vygotsky’s zone of proximal development. In that model when you’re out of your comfort zone, and not in your anxiety zone you’re in the learning zone.
And yet another way of looking at it, still without as catchy a name as Goldilocks tasks, is getting the right match of challenge to your skills to avoid anxiety and boredom and be in flow via Milhayi Csikszentmihalyi.
I learned the name from Dan Pink’s excellent book Drive.
HT: Slava Kremerman