Ted: Well, I think you should move in with him.
Robin: You do?
Ted: Yeah. Yeah. I mean, I see how happy you are. And as much as I love you as a roommate, I want you to do what's right for you.
Robin: Oh! Are you trying to kick me out because of the milk thing?
Ted: It's really annoying.
[flashback to Ted going to the refrigerator and taking out a carton of milk that turns out to be empty:]
Ted: Robin!
[Ted goes into Robin's bedroom while she sleeps and places the empty carton in her bed]
[present:]
Robin: No. I have a system. I put the empty carton back in the fridge to remind us to buy milk.
Ted: Okay, why don't you leave a full carton to remind us we don't have to buy milk?