I rewatched Season 4 over Christmas. And one of the many things that jumped out to me on this watching, was how much Sun has changed. What's going on with her? She bought controlling interests in her father's company, which is pretty cool. She also is blaming her father and from his comments, Jack, for the death of Jin.
The real shocker with Sun is her decision to align herself with from all appearances the real "Big Bad" of LOST Charles Whidmore. What will Sun do? How will this new alliances change the world of LOST.