Usually I dislike this kind of storyline. I watch this show for the mystery and action, not for the relationship things.
However, this one was really out of the ordinary. The editors chose the right good flashbacks, and mied them perfectlly with the bad ones. The music was a perfect match, and (not as usual) I wanted to keep watching what's going on with charlie, and leave the mystery salving for some other time.
This episode is so good I'm writing this review about a year after i saw it, just because i saw its name on the list, and I rememberd.
Thi is a watchble episode even for those who hadn't watched lost from the beggining.