| ...are a lot more common than we might think. Which in itself is rather shocking.
Case in point: I have a pretty good friend who is an excellent public speaker, but "he" (gender neutral to protect identity) just doesn't listen during a conversation. This is what he does:
He: So I think we should do this.
Me: I think we should too. Let's proceed.
He: Because we need to do this and it only makes sense.
Me: Yes, I agreed already. Let's. Proceed.
He: Because if we don't do it, we could be facing some problems down the line.
Me: Okay. I've already agreed.
He: Yep. That's good, because we need to do this.
Clearly he has some inexplicable need to explain himself and make the argument whether or not its required. I find it annoying and a waste of time. Further, I've called him on it before:
He: So I think we should do that.
Me: Dude. Stop explaining and justifying. I've already agreed.
He: (Irritated) I know, I know, but you understand what I mean.
Me: (Irritated too now) I've already bloody well told you that I do!
I think it's possible he's mildly obsessive-compulsive. Maybe I am too -- I'm obsessive about not wasting time with purposeless chit chat when we could be doing what we've already agreed upon. | 
