Dean jumped as Cas appeared next to him. "Cas!" he exclaimed. "There's this thing called personal space." he said as he relaxed. "Also knocking." Cas frowned at him confusedly. "Personal space?" Dean asked. "You know, that thing with the privacy?" Cas shook his head. "I have discovered-" "Okay, no, we're having this discussion." "Surely this is more important-" "No, because you're going to keep doing this. Look, I don't know what the rules up there are, but among humans, personal space is a widely accepted concept. Being physically that close to someone is really only comfortable if you're intimate with someone. Of course, with some people they're generally more comfortable, sometimes they're less. I'm the latter. As is Sam. So, just-" he looked at Cas. "You still haven't moved." Cas moved away. "May I speak now?" "Did you actually grasp any of that?" "I can recite it word-perfectly." "Yeah, but did you grasp it? "Dean." "Does my name suddenly mean the same as 'yes'?" "No, Dean." "Oh, fine, talk." "I think I may have found the location of Lucifer." "Well, why didn't you tell me first?" "You kept interrupting me." "It's called interrupting back!"