It is probably something to do with the fear of being eaten alive, and potentially by a friend or family member. Add to this the psychological trauma of having to kill an infected family member before they turn, they are a truely terrifying foe.
In Canada, researchers have gone as far as doing a scientific study into how long it would take an outbrake of zombies to overrun society, and whether it is possible for the human race to survive such an outbrake. The scientific paper is published in a book - Infectious Diseases Modelling Research Progress.
In the UK, we initially appear to be at a disadvantage due to our lack of guns, and even crossbows. However, most of the guns that are in the hands of the public belong to farmers. They are only too willing to use them to keep unwanted guests off their land. We also have a couple of other advantages. Firstly, we have Wetherspoons. Any zombies wandering in there in their usual uncoordinated fashion would undoubtedily spill a few pints. Their chances of survival would be slim following the ensuing altercations. Secondly, with the size of the holes that council workers leave in our highways and byways, vast numbers of zombies will rot away in the bottom rain drenched pits. Just to be on the safe side though, I think it would be wise for morticians to tie the shoelaces together of any deceased passing their way.
Are you ready? Personally, I'm not that concerned. I figure I just have to be able to run faster than the fatties!