I did dislike Juliet at first but seeing her under Ben's cosh so to speak and realising what she wanted - then I started to feel sorry for her. Felt the same way when Kate kept popping up but I guess it all worked out in the end.
The thing that I loved about the show the most is that despite the mystery and the enjoyment you get out of watching such a show, wondering what's going to happen next - the main thing for me was the characters. The interaction, seeing stories, back history, love lost and found again - it was superb for me.
One of the best highlights for me was the whole story arc involving Desmond and Penny. That reunion on the ship was like a massive release - brought me to tears it did more or less.
Season 6 though was somewhat confusing. Perhaps I missed something but I didn't quite get whether the characters in the present living their happy lives was simultaneous/before/after/alternate universe in terms of events happening on the island.