Martin’s story offers a fascinating perspective on what it takes to stick with habits for the long run. Comedy is not for the timid. It is hard to imagine a situation that would strike fear into the hearts of more people than performing alone on stage and failing to get a single laugh. And yet Steve Martin faced this fear every week for eighteen years. In his words, “10 years spent learning, 4 years spent refining, and 4 years as a wild success.”

Why is it that some people, like Martin, stick with their habits—whether practicing jokes or drawing cartoons or playing guitar—while most of us struggle to stay motivated? How do we design habits that pull us in rather than ones that fade away? Scientists have been studying this question for many years. While there is still much to learn, one of the most consistent findings is that the way to maintain motivation and achieve peak levels of desire is to work on tasks of “just manageable difficulty.