"Why? Why can't you stay?" Dean asked as he was practically ready to plead for you to stay. "It's the second time you leave."

Dean mostly feared abandonment. He had those issues and he feared to lose everyone. It seemed everyone kept leaving. And you've left before, you came back and now again? It didn't sit right with him.

"God forbid you ever stick around!" He said with his tone raised, using force and loudness as a defense mechanism.