Quote from Monica in The One with Phoebe's Ex-Partner
Joey: When she sees he's my roommate, she'll tell him what I did. Monica: What did you do? Joey: Oh, no. I can't. I can't tell you. It's the most awful, horrible thing I've ever done in my whole life. Monica: Okay, don't tell us. We'll just wait till Chandler gets home. It'll be more fun that way.