The vast majority of office chitchat is like a carrier wave in radio. It doesn't transmit much information other than I am a normal human who you can turn to when it is needed. There is a fair amount of politics etc that is conveyed more through body language and dominance dynamics rather than the actual words exchanged.
Except they don't care about you. Someone could burst through the door and skin you alive, but your coworkers won't be in the least bit perturbed unless: 1) Your mutilation was against company policy 2) Some bits of you got on their shirt. Personally, I'd much rather deal with people knives drawn rather than work hard pretending to care if each other lives or dies.
If a coworker I like suddenly passes I'm not going to mourn for weeks, I'm going to say "that's a bummer" and go on with my life. But that doesn't mean I am completely devoid of caring for them.