3. The Return Of Sophia
https://www.youtube.com/watch?v=yqaqT0m02bc With everything that was going on during the first half of the second season, especially with Carl getting shot and Shane becoming more and more deranged, it seemed like everyone forgot about poor Sophia and the fact that she'd gone missing while running away from walkers. Then as the mid-season finale crept up on us and we found out that Hershel kept walkers in his barn due to false hope that they might be cured someday, many of us quickly realized what might be in store for poor Sophia. The sight of an incensed Shane running towards the barn and giving an intense speech about survival before opening the barn door and letting the walkers run free is etched on fans' minds forever. At first it seemed like every zombie in the barn had been shot and Sophia was still out there in the forest, but then two little feet popped out and we all knew who they belonged to. Although Rick has gone on to make some incredibly hard choices since the show began, this is probably the first true devastating one that set him on his current path of violence and destruction even though a few minutes prior he was trying to keep the peace between the two groups.