I've seen several shows gradually go down the drain. Numb3rs and Bones immediately come to mind. But I've never seen anything go from superb to total crap within the change of just one season like The Walking Dead did. It is now painful to watch and thank god there's Shane who at least provides 5 minutes of greatness. The end of the season can't come soon enough, and I know I won't be watching one more minute after that (I should stop now, but my OCD prevents me from quitting mid-season...)
The 1st season was really good overall. There was some melodrama, yes, but it was a zombie show. There were zombies and gore and action. All that is gone in season 2, it's just a crappy soap opera.
All characters have become completely unlikable. And that's really a feat, for the writers to make all the characters unlikable like that. The ideal ending for S2 would be to see them all eaten alive, close up, in slow motion, and with replay of each scene - and that goes especially for the old farm man (I don't care to remember his name) and Dale. At least Shane, no matter how he behaves, he still keeps some action alive. Even Daryl has become a pussy, and doing that to Daryl's character is yet another unbelievable feat for the writers.
It was only the ending of this episode that got marginally better, and that was because Shane finally took over (plus the nice twist at the end). This was the only reason I didn't give it a "1", but it didn't make up for all the hours wasted to get up to that point.