Continuity mistake: When Isabel is helping the daughter make a tree more lifelike, Isabel paints the limbs outside of the round yellow ball shape. In the next scene when the daughter tries to do it, there are no limbs going out of the yellow ball shape. (00:49:30)
Continuity mistake: When Luke proposes to Isabel his shoulders are quite woolly in shots from the front, but shaved in shots from the side. (00:45:25)
Visible crew/equipment: A microphone is visible above the mother when talking to the Doctor about her cancer treatment. (01:37:37)
Continuity mistake: When Ben drinks juice in the hospital his hand moves from the straw down to the bed between shots. (00:58:30)
Continuity mistake: The arrangement of pillows behind Ben changes in the scene where Jackie tells the family that she has cancer (best seen in relation to the star pattern of the sofa). (01:09:35)
Other mistake: When Ben surprises Isabel by hiding in the kitchen cabinet, he is in a deeper cabinet, but when Isabel takes him out of the cabinet it is no longer deep enough that Ben could fit inside of it. (00:02:55)
Continuity mistake: In the scene where Jackie and the children dance wildly across the landing there is a teddy bear sitting with back to the railing. The camera moves to the dancers, and when it returns to the teddy it has turned to the side. (01:14:15)
Continuity mistake: When Jackie talks to Anna on Christmas Eve and the camera is on Anna the only thing you see in the background is a mug with the handle pointing to the side. In the last wide shot the mug has turned around. (01:53:00)
Revealing mistake: The scene where Jackie takes Anna for a night ride in the snow is special for several reasons: Even though it's the first snow of the year and no earlier scene made the impression that it is particularly cold, they come by a lake that's half covered with ice. Both don't wear gloves (horse riders usually wear gloves even in summer!), and, in spite of the cold night, their breath doesn't make any clouds. (01:20:35)
Continuity mistake: When Jackie talks to Ben on Christmas Eve her hands are down, but when the camera angle changes she is fiddling with the strap of his jacket. (01:48:20)
Continuity mistake: When Jackie and Isabel are talking, while Jackie hands out props to the kids for the Thanksgiving play, Jackie removes a book from a shelf and holds it in her hands. When the shot changes, she is seen removing the book from the shelf again.
Continuity mistake: The stone pillars in the middle of the arched windows of Luke's and Isabel's apartment is only visible from outside, not from inside, e.g. in the scene where Isabel helps Anna with her painting. In the scene where Ben calls his mom in hospital there are even two stone pillars. (00:49:35 - 00:53:15)
Continuity mistake: In the scene where Luke and his children have a talk on the lakeside Anna's hair is perfectly tied to a ponytail in shots from the side and from the back, but there's a lot of loose hair flying in the wind in shots from the front. (00:16:25)
Continuity mistake: At the end of the movie when it shows a snapshot of the whole family taken with a timer, it ends with a close-up where only Jackie and Isabel are in the frame. The close-up is taken from a different picture because the background is now out of focus.
Continuity mistake: In the breakfast scene at the beginning, two rounds of toast pop out of the toaster very dramatically. But the model of toaster used does not pop, there is a lever clearly visible that is used to manually crank the toast up when the filaments have been turned off. (00:02:45)
Answer: You can see the reference in Kevin Smith's first movie Clerks. Whether or not she's referencing that particular movie or not is debatable.
Nikki