Nick Valentine is literally the only person in the game I care about. I did the Castle mission, and all but one guy got shredded. I think I may have killed one because he walked directly into my line of fire, and my guns are stupidly overpowered, but I don't care. Unlike Skyrim, I feel a general sense of apathy and often antagonism against the NPCs in Fallout 4. I'm not sure why that is, but I'd be happy to eliminate most everyone I've encountered so far.

Perhaps it's because they refuse to buy or use washing machines...