"We've talked about this before," Sam says, raising his head to look at Castiel properly. "You don't owe me, Cas. I'm good with you wanting to be good and patient for me because you want to, but not because you feel you have to out of some need to balance scales."

It was something that was always likely to be difficult for Castiel to understand and he might always feel that way. But Sam did his best to explain the difference if he could.