Niles: In every healthy relationship, I may ask for an occasional - very occasional - irrational demand.
Daphne: What do you mean?
Niles: Uh, a thing we insist the other do or not do, and the other one has to do it or not do it, without question.
Daphne: Is that fair?
Niles: It is. Because we each get one, and only one, for our whole relationship.
Daphne: Well, if it's important to you.
Niles: Then it's agreed?
Daphne: Agreed.
Niles: Good... Oh, I've got mine.
Daphne: Already?
Niles: Yes. Uh, I want you to promise never to come to this dog park again.
Daphne: What?
Niles: I know it sounds extreme, even unreasonable, but that's the beauty of the irrational demand.