The Yoga Sutras say that we move towards the goal of Yoga by practice and detachment. When we are able to do both of these then we know Yoga is working.
The order is important. You practice and then something happens. That something is usually what lets us not be so attached to a behavior or outcome. In this context detachment is always positive. In the West we tend to view detachment as meaning that we don’t care, when actually it is exactly the inverse. When we are able to be detached towards someone we are able to be deeply compassionate towards them. In a sense, detachment means you don’t project your stuff onto other events or people.
Practice is important because Yoga is about experience and practice. We do something, we try it out, and then we realize something or we don’t realize something.
Practice and detachment feed each other – practice enables detachment and detachment enables practice.
Why is detachment so important? Because, the more detached you are, the calmer your mind is. The two big goals of Yoga are a calm mind and seeing clearly.