Colton Harris-Moore, also known as the Barefoot Bandit or Barefoot Burglar, was a bit of a goldilocks, although of course his fame owes itself more to his “borrowing” of cars, airplanes and boats than his slipping into strange kitchens to make himself a sandwich.
As a modifier, goldilocks means “just right,” possessing neither too much of one quality nor too little of another. For instance, a goldilocks dose is a dose of medication that is high enough to cure or effectively manage a condition but low enough that there are no unwanted side effects.