I started watching Lost a few months ago on Netflix, shortly after finishing 24. Ever since the end of Season 1, Michael and Walt have been my favorite characters. I find their relationship touching, with Michael willing to do ANYTHING for Walt, even murder.
This episode is basically one giant flashback telling us what Michael has been doing since the end of Season 2, since he was absent in all of Season 3 and up until last episode this season. It's believable how the others played off of Michael's emotions and suicidal additude.
For those complaining about it being unrealistic, well was Lost ever realistic? Mysterious island? Pandas? Polar bears? Horses? Ability to see the future (later revealed to be time travel)...seriously, it's Sci-Fi with hints of Realism. And it's insanely entertaining.
Michael's return is awesome. This is a very underrated episode and it answers the main question that has been on my mind since the end of Season 2: what the hell happened to Michael and Walt?
Great episode, highly underrated.