When you are enviously looking at the student on the mat next to you fold their foot up by their ear, focus internally on your breath, close your eyes and take your awareness back to your flexibility of mind! As our minds become more flexible we are able to accept that we are all different & we all shine in different areas. For me as a yoga teacher, the student who discovers more about themselves & their internal world through their physical practice is learning more from yoga than the student who can easily flow into a difficult physical practice. So remember that yoga is about more than just physical postures; that the asana are just one of eight areas which Patanjali focused on as the practice of yoga.