I was talking with a freind the other day, she is new to Yoga and was describing her struggle to come into Half Moon. Half Moon is a standing balancing pose which also opens the hips. My friend's struggle resulted from the way the instructor built the pose - from the top down; coming from a standing position and lifting the leg backward. My recommendation was to try building from the bottom up - coming from a forward fold and lifting the leg backward. This advice helped my friend and the next time she saw her instructor, the instructor told her that was wrong. I was shocked to hear that!
The Beautiful thing about Yoga is that each person has a unique practice, an individual journey. Never will 2 people practice the same and never is anyone's practice wrong. We, Yoga instructors, are meant to simply guide you on your journey, to offer knowledge and encouragement.
There are a multitude of Yoga traditions and you will find that with every tradition translation and interpretation vary. A pose called "Crow" in one tradition may be another traditions "Crane", an inhale motion in one class may be an exhale motion in another. Different styles focus on different body parts and function - this is why one style teaches to build from the top down and another from the bottom up, or any other way you can use to build a pose. So does this mean that one is right and the other wrong? Absolutely NOT. Yoga is created and recreated each time you come to your mat, every moment is transformative. Try it from all angles, motions and mindframes. The only way a pose is ever wrong is if it is painful or puts you at risk of causing yourself harm. Other than that - it's your practice, it's your pose, it's your peace of mind - make it what you want it to be and ENJOY!