The Walkers Are Evolving
For argument's sake, let's say Eugene is right and the odd behavior means the walkers are indeed evolving. This goes against the storyline of the comics, but at this point, I think it's safe to say no one's really concerned about that anymore. Evolving walkers would raise the danger for our survivors tenfold, to a degree that I'm not sure I even want to explore. Imagine someone trying to fight a walker with an actual personality?! The stress! Honestly, if the show does go down this route, there's a chance I could respect such a ballsy departure from canon. But it better not, because it makes no sense and we have been through enough, thank you very much.