I came across this question in a book by Chip and Dan Heath, Switch (Broadway Books, 2010).
More specifically, the question goes:
“Suppose you go to bed tonight and sleep well. Sometime in the middle of the night, while you are sleeping, a miracle happens and all the troubles … [you’ve been brooding over] are resolved. When you wake up in the morning, what’s the first small sign that would make you think, ‘Something must have happened — my problem is gone’?”
As it turns out, if you answer this question very specifically you’ve probably just given yourself the first concrete step to solving the problem.