Guard towers were blown up last season when the governor attacked. This season they're shown perfectly intact.
Michonne says she is planning to go to Macon (in Bibb County) to look for "him". Later, Michonne is shown with a map and has her finger on Macon County.
The main characters seem to have complete amnesia about the recall and thinking behaviors they witnessed in some walkers when Lizzie is trying to explain that very fact.
While Rick and Carl are discussing the pig that seems to be unwell, they are oblivious as to what is wrong with them - at no point does it seem that they considered involving Hershel, who is a veterinarian. Rick and Hershel are even shown talking in the plant growing area and Rick does not raise the issue of the pig.
The group seems oblivious that they need build better living conditions and defenses, even after all they've been through and seeing the accomplishments of others. Although Atlanta is nearby and perfect neighborhoods surround them, next to nothing has been gathered or built. Even the guard towers (that had already been climbed once by an enemy sniper) are still not being properly used.
Rick had seen walkers smart enough to turn doorknobs, use rocks as tools, and be agile enough to climb high fences. Despite having 30 days, the prison still hasn't even been fortified from such thinking or skilled walkers. In addition, Rick and his people had seen how easily The Governor/Woodbury and Morgan had dealt with walkers by building walls and/or traps. Despite Rick's group having materials all over and weeks to do the same, walkers are allowed to gather at the prison fence and watch them.
Rick had seen walkers smart enough to turn doorknobs, use rocks as tools, and be agile enough to climb high fences. Despite having 30 days, the prison still hasn't even been fortified from such thinking or skilled walkers. In addition, Rick and his people had seen how easily The Governor/Woodbury and Morgan had dealt with walkers by building walls and/or traps. Despite Rick's group having materials all over and weeks to do the same, walkers are allowed to gather at the prison fence and watch them.