This episode has no cold open, the second season 9 episode where it is absent.
While discussing Andy's behavior with the other team members, Meredith is holding the mug that Kelly made for each of them in season 5 episode 7.
When Andy sings, "Who's that girl? Who's that girl? It's Andy!", he's imitating the intro to the show, New Girl (2011) with Zooey Deschanel.
Amy Hill plays the role of Nail Salon Manager. On Seinfeld's "The Understudy" she plays a nail salon employee.