'Resistivity' sounds an awful lot like 'resistance,' but they're actually two different things. Resistivity is a property of the material an object is made of, whereas resistance is affected by several other characteristics of the object. Every material has some electrons that are free to move around between atoms and other electrons that are tightly bound to the atoms. When the free electrons try to flow through the conductor, they tend to collide with the outermost electrons of the atoms, which impedes their movement. Materials with more of the tightly bound electrons, and therefore fewer free electrons, have a higher resistivity.
Going back to my time at the mall, there were some people that were moving along in the crowd, trying to get to the stores, just like I was, so they really weren't affecting my progress. These people and I were like the free electrons. Then there were other people that were just standing around, looking in the windows, talking to friends, or simply taking a break. It was these people that were difficult to get by and impeded my progress. They were like the tightly bound outer electrons of the atoms that just wouldn't move. If I had gone to another mall that had fewer people standing around and more people moving, then that mall would have had a lower resistivity than the first one.
