First, I enjoy the show as entertainment, so I'm willing to suspend disbelief. I ignore the disappearing bodies and such fornthe sake of entertainment.
That said, there's one thing about the whole zombie thing that bugs me. Assuming a massive outbreak like the show, you suddenly have lots of dead bodies walking around. And these bodies are rotting as they walk around. So, how long until these walkers decompose to the point where they can't walk around anymore? How long until the legs fall off, or the upper body structure simply gives out and the body just can't stand under its own weight? I'm thinking that within a year (how much time has passed for these guys?), the sheer number of walkers will be reduced to the point where the risk is closer to that of street crime, or more possibly like a bear attack on a hiker,