First couple of seasons of The Walking Dead were really good. Then Frank Darabont had a falling out with AMC over how much money they were willing to invest so he left the project (it's not clear if he walked of if he was 'encouraged' to leave). But that's part of the reason why there was so much footage shot inside the Prison towards the middle and end of Season 2. It was simply cheaper than exterior filming.
I'm still watching it now and it's started to pick up again but it's definately fair to say it fell a bit flat on a number of occasions.
Now Breaking Bad, on the other hand, well that managed to sustain things for a full 5 seasons and they had the good sense to finish it with people wanting more. Not sure that could ever be made into a Pin theme though..... ;-)
Haha, mentioning that groups a load of us squarely in the same age bracket. That's also where I first saw him and he's done a load of good stuff since then (Teachers included).