Dark Vamp: I watched lost for awhile, but they started to have a very strange TV schedule where they were skipping weeks - I ended up missing a couple of episodes so after that, I just stopped watching.

Now Dexter - that is an interesting show. I did not start watching until about 1/2 way through the 2nd season, but was able to watch every episode before that to "catch up", and haven't missed one yet.