it's because the show, while ridden with shortcomings in plot continuity, still manages to weave an epicly thrilling tale about some very interesting characters that the viewer comes to love (and hate) over the course of the first 20 episodes or so. Much like a Dan Brown novel, the actual stand-alone quality of the plot and its composition are not so important as the feelings aroused in the viewer. It can be entertaining, even if it's full of holes.