Really? I just finished re-watching it and found the later seasons to be incredible. Better than the first two. Especially the climaxes of seasons 3, 4, 5. I definitely got more out of the second viewing, I had much more focus on character arcs than plot.
Different strokes, I suppose. There was a lot more black comedy near the beginning instead of just the grim realism of people making the same mistakes over and over again.
Well, the first few episodes at least. The show starts out awesome and gets progressively more depressing with no payoff episode after episode.
By the end I was watching out of sheer stubbornness.