The hanukkah celebration is warm and close-knit and cozy, while the reality is that they're hiding in a building where the Gestapo could barge in at any time. This contrast is shown when it mentions a car passing by in the background and a dog persistently barking, both of which foreshadow imminent danger. In the annex, people are exchanging gifts--and warm feelings, in sharp contrast with the cold, merciless Gestapo.
