they don't always get to have the last word if you choose your dialogues correctly.
That's why I don't feel like I'm roleplaying, why can you only say your point on certain moments? You become mute to certain words if you don't choose the proper lines.
That's more like playing a robot and not a real person to me.
That being said, personally it's not about having the last word but just being able to say an actual reasonable point not just taking everything the NPC says to you.
Doesn't mean NPCs have to listen to reason though because some people don't in real life, makes it realistic that way.