I was amazed as I watched how many of our characters are taking on the characteristics and lines of other characters. I was blown away by the scene between Jack and Sawyer about whether the c-4 would explode or not. It was like watching any season 1-4 scene between Jack and Locke...except Jack is now Locke and Sawyer is Jack. Some other lines I noticed:
Jack: Whatever happened, happened...why won't you believe me (I can't remember the exact way he said it.)
I know there are others, but I'm suddenly drawing a blank. What did you notice?