Jack: Lemon, today is the first day of the rest of your life; and what is the first thing you need to do?
Liz: I have to break up with Dennis.
Jack: And if you don't break up with him now?
Liz: He'll just keep showing up at work to sell beepers; we'll just get more and more tangled up in each other's lives 'till I can't even get away and we're just like... Oh, my God!
Jack: That's right! He's the Rat King. And there's only one way to break up with a rat, you have to cut him off completely.