Moderation.

Train your eye and your vision lusts after colour.
Train your ear , and you long for beautiful sound.
Delight in doing good, and your natural kindness is blown out of shape.
Delight in righteousness, and you become righteous beyond all reason.
Overdo liturgy, and you turn into a ham actor.
Overdo your love of music, and you play corn.
Love of wisdom leads to wise contriving.
Love of knowledge leads to faultfinding.
Way of Chuang Tzu