Detachment keeps your mind calm and serene, but the moment you show any attachment, you put tension in the mind. A yogi is one who has a tranquil mind, a neutral mind that has found the zero point, so his or her judgment will be absolutely clean and perfect. To find neutrality, one should be detached, with neither likes nor dislikes; if the mind leans to either of the sides, it will lose its power of judgment. That neutral point can be achieved only by a completely detached mind. That is the goal of Yoga: neutrality, tranquility, equanimity.Samatvam yoga uchyate, says the Bhagavad Gita. Equanimity is Yoga. To such a mind permanent happiness is its property.