At first blush, "Lost" seems like an impossible concept: a bunch of people stranded on a mysterious island. How many story lines can you POSSIBLY take from that before the idea's been sapped completely dry?
It's a legitimate concern, but in the case of "Lost," totally unwarranted. "Lost," unlike many shows today where the plot drives the characters, is in fact the opposite: the characters drive the plot. This isn't "CSI" or "Law and Order," where each week is a variation on the same theme. On "Lost," you have a group of fascinatingly different, tragically flawed characters who must somehow learn to survive together, while at the same time trying to keep their secrets hidden. That's a method for disaster. After living together for a long time, the characters are going to find out it's impossible to keep their pasts a secret.
Yes, there's a monster on the island. Yes, there are mysterious happenings.
Yes, a sense of dread often hangs thick in the air. But to me, the exterior problems presented by the island itself are NOTHING compared to the INTERNAL problems the characters must face, both with themselves and with each other. That's where the REAL drama lies. And it's fascinating to watch.