For me, it was some kind of bug.

I was doing Run Goodsprings Run, and I got a map marker way over in scorpoin gulch, so I walk over there, and what do I see? Sunny, waist deep inside a boulder, pointing her gun at me and screaming battle dialogue. And then I got attacked by a Giant Radscorpoin and died.

What about you?

Well on my unarmed playthrough I went up to sloan to fix up sniffles leg and I saw a red marker and went at it only to hear a menacing growl turned the corner and BAM deathclaw alpha male just casually wandered into sloan and mauled me.

Maybe I'm just a terrible person, but I found it hilarious when Papa Khan got everyone in the Longhouse to butcher Karl at the end of Oh My Papa. Once he lost his head before he got up and the other time, he got near the door before getting riddled with bullets and rag-dolling around the tables after.

I also liked how Captain Parker continued shooting Keith's lifeless body non-stop after he insulted his wife (must have been a bug). That and how Benny says "What... the [censored]!" over the intercom after you kill his four goons.