I have to suspend the whole 'endless appetite with no functional digestive system' thing. That and the 'muscular coordination after rigor mortis' thing. That and the 'acute sensory ability that's stronger than it's own body rot' thing. After that, I just have a mindless good time with it. 
(I think a scene where Rick kicks open a toilet stall to see a zombie in the middle of a bowel movement would be hi-larious.)
(I miss Firefly.)
Also don't forget gravity and its effect on bodily fluids all the blood would be down in the ankles and feet would it not?