In the episode where Ross and Monica's "Nanna" dies, back at Monica's apartment, Monica and her mom sit down and talk about Nanna. After telling Monica how picky the deceased grandmother was, Monica starts asking her mom if she would tell her (her referring to Nanna) about the constant nagging, and her mom, getting the hint, says no. Monica then pulls her hair behind her ear, and her mom reaches out to fix it, but decides not to, and compliments Monica's ear rings. It cuts to another shot, then back at Monica, but her hair is in front of her ear again! Then, it pulls away, then back, and the hair has mysteriously pulled itself behind her ear again! I think it does it a few more times after that. Well, there you have it.