Yoga is a way of life not just the Asana practice. Its not just about looking good but feeling good on the inside. When you do yoga without wanting the results of achieving a certain posture, then it happens. Open your mind as well as your body. In fact when you open your mind , the body takes care of it self. Try it:)
Not to say that you should not want to look good:) Looking good in turn makes you feel better about your self. So get the right gear for your class, something that makes you want to practice in them. But when in practice forget about it:)