I think you're purposefully being obtuse here. You know that's not what I meant based on my very next line:
"It's a bit jarring that I can't feel like I've become friends, or enemies, with people after I've completed their quest. I can't ask follow up questions, ask them how things have been since I helped / harmed them...I just get a one liner and that's it."
This certainly was the case in Fallout 3, where after completing a quest you can ask follow up questions about how things have been going since you completed the quest. It was minor, sure, but it was a minor touch that made the game feel slightly more alive.
After siding with the cannibals in Arefu, I can continue to have small talk with them, the wife can bake me human pies, everyone has some new dialogue reflecting how I completed the quest, I can feel like I've become a part of the neighborhood.
Again, none of this was advanced, but that' snot what I was looking for. I was just happy that the world reacted to what I did in some small way and that the npcs seemed to be my friends now and that I can still interact with them.
Obviously this doesn't matter to you, but it did to me, and I'm a little bummed that this wont be the case in Fallout 4.