The dialogue between sisters:
Grace: “Millie, let’s play pretend like we are rockstars!!!”
Millie: “No! I want to be a mommy!”
Grace: *rolls eyes and then a big sigh and says: “Fine. Go make me some potato salad.”
And we now see that what encompasses being a “mother” is a servant figure that mixes up potato salad on demand. Glamorous.