The Chiro told me that bad shoes make your body subconsciously compensate by changing your posture and the way you walk. One of the first things he did was ask me to walk a few steps towards him and then stand. He looked at my feet and my left foot was pointing outward at an angle when I stood there. That, he told me, was the result of crap shoes and a surefire indicator I was compensating for them and that my sciatic nerve was being aggravated.

I ignored him for about a month and he scolded me about that so I went and got some good shoes. I could feel the difference as soon as I stood up in them. I took a few steps, stopped and looked at my feet, and they were both pointing straight.