Mu - Friction

I think friction happens because when two surfaces  resist each other, they cause tension. For example, today in class, we observed how a shoes reacts to being slid against different surfaces. The surface with the most mu is carpet. It was hard to slide the shoe against the carpet. There was definetly friction. I think polished wooden floor would cause the shoe to have a bigger value of mu. I think this because I find it impossible to glide or slide against polished wooden floor. It was hard for the shoe to slide against carpet because of the friction it had between them. If we were to test how a shoe slides against a wooden floor, maybe the amount of friction would be greater. I'm not sure but it is just a theory.