To paraphrase former NBC executive Warren Littlefield: The things that scare us make the best TV shows - which is something programming executives should consider in this age of un-funny sitcoms. Socially inept, ego-centered characters on "Seinfeld," or central gay characters on "Will & Grace" don't seem much like scary material now. But at one time they did strike fear in TV network executives who believed that, in turn, viewers would fear them as well. Now there is a scary sitcom idea - floating around for sometime -- that no network has the stomach yet to schedule. It's …