The fake eyebrows on Matt LeBlanc melted several times due to the lighting and had to be replaced.
When talking about getting his eyebrows waxed, and Phoebe jokes about Joey being high maintenance, he tells Phoebe she dyes her hair and complains about that double standard. Matt LeBlanc dyed his hair for most of the series.
Rachel, who is notorious for returning gifts, is wearing the scarf Gavin gave her for her birthday in this episode.
When Molly arrives at Ross and Rachel's apartment to take Emma to Rachel's mother's she is wearing the same scarf that Monica was wearing when she arrived at Rachel's office in "The One with Phoebe's Rats." In that one when Rachel asks Monica "Do you see what the guys see in Molly" her reply is "I wouldn't kick her out of bed."