Quote from Chandler in The One with Two Parts: Part 1
Chandler: All, right now look at her and tell me she doesn't look exactly like her sister. Joey: I'm saying I see a difference. Chandler: They're twins. Joey: I don't care. Phoebe's Phoebe. Ursula's hot. Chandler: You know that thing when you and I talk to each other about things? Let's not do that anymore.