What happened when the Karr family left the Bridge Cafe soon after Mary's birthday?

Mary's family went out for a nice dinner together at the Bridge Cafe. On their way home, Charlie became inexplicably depressed as they drove back into the city and tried to wrestle the car wheel away from Pete while he drove. To regain control of the car, Pete was forced to punch Charlie in the face, knocking her out. When Charlie woke up, she still wanted to fight and scratched at Pete while the girls cried in the backseat of the car.