It place you above the mundane. It doesn't let you sleep while you're awake. Teaching can be a dream, but you have to be awake to live it and appreciate it. So, I'll tell him that the good teacher has some fun each day in in his or her classroom. I'll tell him to let his teaching become more playful and enjoyable, and the students' learning more playful and enjoyable.
Every day be sure to play in the classroom.
But, don't play at it. Play is a paradox. Good teaching takes long hours, hard work, and risk-taking. I wonder if when entering their classes their students are reminded of those horrible days when they were met at the door by their prom date's father. I think playfulness is itself a creative, emancipating state.