The one issue that remains for me is the use of flashbacks. While the creators utilize this device in order to explain how a sociopathic serial killer like Dexter can navigate the world undetected -- through the teachings and direction of his adoptive father -- this is something that stretches beyond the ken of how much I can suspend disbelief. There obviously has to be some sort of suspension of disbelief to accept that a serial killer is also one of Miami's top forensic analysts, and that much I can accept. The flashbacks reveal that Dexter's adoptive father rationally taught him a moral code to channel his instinct to kill, and that takes this idea too far for me. The pathology of serial killers is that they cannot be taught, and while implicitly this has to be accepted if the underlying premise is to be entertained, the frequent use of flashbacks over-stresses this to a point of complete disbelief. By the end of the first season, however, this was largely relegated to the back burner, as the plot had thickened sufficiently that the viewer is more interested in its resolution than its realism.
Michael C. Hall is compelling in his portrayal. Stylish show, excellent writing notwithstanding the flaws, and fun. On to the second season.