For me,It used to be the ability to function, and be totally alert after having only for to six hours of sleep at night During my childhood I had what I call a distinct advantage over any of my family members as I would arise at three,or four in the morning,be ready to go to school,and the beauty of it was the house was quiet! I had a few hours a day completly in peace before the din of the day started. Also,I was [still am] a very curious person and I had the extreme energy level to explore the natural world around me.