This is one of my favorite moments in the movie: Gus makes a joke about Isaac’s disability and then Isaac is like, “Not only am I going to call you out and refuse to accept you making me the butt of your joke; I’m also going to do it in a way that shows you that I am funnier than you are.” And Gus is momentarily defensive and then like, “Okay. Yeah. Fair enough.”
Nat improvised that line, by the way. Such a great actor. He’s going to be so amazing as Q in Paper Towns.