For some reason, I kill Manny Vargas in every single game. Funny enough, I usually put a bunch of C-4 around his bed and go in the corner and BOOOOM!!!! Something about that message on his computer always rubbed me the wrong way.

I also always kill Old Lady Gibson. I regretted it the first time because I like Nuka Cola Trucks, but now I always want that special Sawed-Off she has so bad that I just cap her.

I kill Boone every playthrough, but not for an odd reason.
I just hate him with all my heart and think he is a psycopath that don't deserve to live as he will only hurt others.

President Kimball, even if I'm working for the NCR I let someone cap his ass.

Sunny Smiles.
She's the worst voiced character ever.

Boone is just kinda there for me. I'm starting to like Veronica. I've got him wearing the Remnants Power Armor and he is pretty much unstoppable. I'd like to give him a major weapon and fight him lol.

Now that I think about it. I think I'll kill Lily.

Her dog got killed on my last playthrough for the first time ever. I'd almost of rather it been her. haha.

I kill Manny Vargas alot. I take his rifle from him.

For some reason I always kill Fantastic.... I do the quest and just get the sudden urge to let him meet Benny's pistol Maria. Idk why one playthrough I tried not killing him and just couldn't do it.