Forum:KB: ROTS Battle Droids with personality

I was watching Revenge of the Sith last night and was reminded of my least favorite part of the entire Star Wars saga: the battle droids that act like humans. In Phantom Menace and Attack of the Clones the droids were droids, and they acted how programmed droids would. But in Episode 3 they wince in pain when hit, they show human emotions, and their movements aren't efficient and robotic like a designer would have programmed them to do. Just watch the Vulture droids take off in the big space scene at the beginning of the movie. Metal mass-produced droids moving and acting like humans gets to me. But enough of my rant... onto my question.

How is the sudden evolution of the CIS battle droids explained canonically? Obvoiusly in the real world it probably had something to do with the droids acting like that in the Clone Wars cartoon that had just come out, and the fact that everybody hated Gungans (except me) and George needed to shift the comic relief to something else. But in the GFFA is there an event of piece of technology that caused the shift?

PS: Episode 3 is riddled with anthropomorphic droids and vehicles that seem out of place. Like Grievous' crawling/rolling vehicle, the vulture droids, the battle droids in the first half hour of the movie especially (one gets mad and kicks R2, one sarcastically says "You're welcome" after Grievous takes the lightsabers from it, etc.)