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 why we celebrated a show with such a violent, dark premise.