NovemberMike said:
Imagine you are talking to somebody who is saying something interesting. They get to the end of a point and pause. Do you immediately jump in and say something (remember that you are interested in what they have to say) or pause for a half second or so to see if they keep on going?
What everyone is thinking of here is how people talk in movies, where they have a script and know exactly when to see their lines. The dialogue in this is actually much closer to reality, especially given its serious nature.
I was just checking and episode of the O.C, and there's this blond women talking to this guy, and he starts talking like mad.
Usually when someone is saying something you want to listen you pay attention, and normally you don't start jumping around like a monkey trying to do movements, you stay still, you might move your arm a bit, scratch something, but the person that is doing the talking is normaly doing the walking when they have something to show, or somewhere to go.
Obviously, Mass Effect is not without fault, but hey, it's a game, it's not a movie.