It is, as you say, really impossible to put yourself in another persons shoes. I think the reason we do is a form of showing our compassion and trying to gain an understanding of what we can do as outsiders to help with issues that arise, our empathetic nature.

I did like your friends thought - Ah, it is like you are able to walk, but if you needed to sprint, your body just can't do it. - I have felt that, I think maybe a lot of people have, it is just the first time seeing it pointed out in that manner. So we stumble along the path to a somewhat recovery.