When I got Kacey and Kiri from a shelter, their records had identical descriptions even though they're not exactly the same age--that led me to believe that they were fostered by the same person until they were old enough for adoption. Kacey's extremely gregarious and isn't at all shy around strangers. Kiri runs and hides until visitors go away.

As for the ferals I've taken in, they all run away when they hear somebody at the door. But some will come out while visitors are here, while others stay hidden. Angel, who had human contact from the earliest age of all (he was born in my house), is the most timid.

In other words, cats will be cats.