As 'Dexter' signs off, a look back at why people fell for such a gruesome show

Watching a serial killer plunge a giant knife into table-bound victims wrapped in plastic may not seem like an enjoyable way to spend an hour, but for the past eight years, "Dexter" made it work. The grisly, critically-acclaimed Showtime drama ends Sunday, and now, we're left to ponder why we were not only intrigued by, but celebrated, a show with such a violent, dark premise.