Dean had been working with the Castiel for well over a year now. He had made the appropriate adjustments it took to go from not believing in angels to suddenly having one in your inner circle. He had grown accustom to his weird way of speaking, never changing clothes, and blank expression to the point where they were almost comforting to him now. However, there was one thing Dean had never been to able to fully get used to, and that was when the other man would randomly appear out of NOWHERE right next to Dean when he was deep in thought.
"Son of a bitch!" he yelped and jumped far more than he would have liked to...though Dean would argue in a place like this he had a reason to be jumpy.