Biff's Grandma (Uncredited): "Biff!"
Biff: "Yeah, yeah, yeah."
Biff's Grandma: "Where you goin', Biff?"
Biff: "I'm going to get my car, Grandma!"
Biff's Grandma: "When are you coming back? My feet hurt and I want you to rub my toes some more!"
Biff: "Shut up, you old bag."