Nice cactus! Don't let the obvious blind you to the important

There is a TV ad. out at the moment based on the 'spot the difference' game. A couple sit in their lounge and the contents of the room change. In the final shot our attention is immediately drawn to a large inflatable dinosaur dominating the room while the voice-over says "nice cactus" refering to a small cactus which has appeared, unnoticed, on the coffee table. This advertisment highlights how we overlook the important in favour of the obvious. We do it all the time. An example from our yogasana would be noticing the hand of the lower arm touching the ankle and the verticality of the upper arm but not seeing the rotation of the spine while watching a demonstration of trikonasana. Then, mistaking the obvious for the important, when we practice trikonasana we displace the torso and bend the leg in an attempt to reach the ankle and yank the upper arm behind us to get it vertical while barely twisting at all.
This trait of focusing on the obvious makes it almost impossible to understand yoga just by reading a book or from watching a DVD - we fail to notice the important. For this reason it is helpful to work with a teacher who has understood what is important in a posture; to work with someone who can direct our attention away from the obvious to the important. But first of all we have to realise there is a difference between the two.