My FC and I can be quiet chatty outside of dungeons, but we know there's a time and place for talking. We stay normally quiet in dungeons unless someone needs to say something pertaining to the dungeon. Cos we know stopping to talk conversation could mean trouble. A missed AOE here, a missed heal or rebuff there. I like quiet runs since it lets me focus on the job at hand. Chatting at the wrong time can be a major distraction.