I want to play like Federer, so I wear ballet slippers to play tennis.
Seriously, my tennis shoes were chosen to fit me differently than my (very expensive) New Balance running shoes. I have NB 'walking shoes' as well and they are hard for me to do my workout DVD's in because the sides are so high it rubs my heels when I do side lunges and other things. So I have running shoes, tennis shoes, walking/whatever shoes, and still need a pair of cross trainers or whatever for my dance-y/kickboxing/workout stuff. #firstworldproblems
Pros should stop wasting money on coaches and doctors and just read the experts on this forum.