While it looks like Bob has his own personality, it turns out that it was just some code that was installed into him by someone that made him act like a personality...
The Warrons appeared to have become more human after making contact with humanity. However they had those "human" traits from the start. They once had a rich culture before their repressive militaristic world government's stamped it out, reducing them to their one dimensional state. Earth culture spread via contact with humans served as a reintroduction that just brought forth long suppressed urges.
Double Subverted: But when the rogue code is removed, Bob begins acting strangely, doing things that a robot shouldn't for no logical reason, so he developed a personality after all.
Zig Zagged: Bob develops a personality through hanging out with Alice, but it was just a software update, only it was a printer update. Except it is noted to have occurred in other robots after the printer update. It may very well be a Good Bad Bug, except for those of the same model who developed a personality without it....
Averted: Bob is a robot through and through. A logical construct, and remains nothing more than that.
Enforced: As a modern retelling of Pinocchio, Bob has to become humanlike by the end for it to stay true.
Lampshaded: "Have you guys noticed Bob acting more like Alice since she began hanging around him?"
Invoked: Alice wants to convince Bob to become a full AI, and the first step is to introduce some illogic into his system. So she drops a Logic Bomb telling him that humans can create humans, and since he was designed to grow, he'll become like a human too.
Exploited: Charlie hires Alice, Alex, Alicia and Allie to spend lots of time with AI's Bob, Billy, Ben and Zho'heli-tol in order to turn them human and create superlative ship AI's for his fleet.
Discussed: "It's a bit depressing to think about actually, humans are a cultural steamroller. Will there be any alien culture or AI that develops and maintains independence from us?"
Conversed: "Aww, look! Alice taught the toaster to feel love!"
Deconstructed: Bob gains his humanity. Unfortunately, Bob becomes an outcast among his human companions, who still treat him like Just a Machine. Bob also can't fit in with the other robots because they find his new-found humanity disturbing.