Lily: I thought you deleted his number.
Robin: I did, but it turns out, I memorized it. You can't delete contacts from your brain, Lily.
Lily: Well, you have to try. If you ever want to have closure...
Robin: I am never going to have closure. Okay? Closure doesn't exist. Okay, one day, Don and I are moving in together, and the next thing I know, he's on a plane to Chicago. It just... ended. And no matter how much I try to forget that it happened, it will have never not happened. Don and I will always be a loose end. We'll always be...
[elsewhere, in Ted's classroom:]
Ted: Unfinished.