At about the 26-minute mark, as Edith and Stephen are walking in the snow, they stop to comment about the rambunctious children, and even before the flying snowball hits him in the head, Stephen grimaces in anticipation.
After the boy drops a Christmas ornament on Brenda's head, his father chases him around the tree yelling "Tommy, Tommy", but once the camera switches angle to the top looking down on the tree Brenda and Tommy point up to see the boy who had thrown the ornament and Tommy throws his own ornament up to the boy. At that point the father is heard yelling "Jackie." This is the actor's real name, not the character's name.