TWD lost its soul when Carl died. The whole point of Rick's character, and by extension the show, was to protect his son and try to build a better world for him.

At the time, I thought they just killed Carl because the actor was going to college, even though he said he was good to keep working and studying at the same time. Now, it's clear that was just an excuse. The producers just couldn't stand to have a positive father-son relationship in their show.