Quote from Monica in The One Where Chandler Doesn't Like Dogs
Phoebe: You know, if you want, we could sneak the dog back and Chandler wouldn't even know. Monica: That's not going to work. Phoebe: I've had that dog for three days, and Chandler had no idea. He's not so smart. Monica: Hey. I didn't know either. Phoebe: Yeah, but you kind of knew that something was going on, didn't you? Monica: Yeah, I knew.