"To be playful and serious at the same time is possible, and it defines the ideal mental condition."

"Many teachers continue to equate playfulness with frivolity, then complain when students are quiet and un-responsive. They offer examinations and grades as the goal of the class, then are surprised when students are concerned more about what will be on the final exam than larger conceptual issues. Students remember more, think more, and understand more when they enjoy the process."