There is nothing not sad about this scene. 1. The fact that he's sleeping at work. 2. The look in his eyes that screams "help me". 3. The fact that he has a home but regardless of what happened or will happen, he won't ever be allowed back. 4. How he has the bunker with Sam and Dean but he thinks they won't want him after everything with Heaven. 5. How unwanted he feels. 6. The fact that Misha was homeless so knows how this feels and portrays it perfectly.