Scrooge's Heel-Face Turn, especially his reconciling with Fred, who welcomes him in open arms. Janet is cynical but still gracious. When he tells her "I was in love once. Can you believe that?" and Janet sincerely answers "yes".
Scrooge apologizing to the solicitors, and giving a very generous donation, so generous that the two can't hide their excitement.
The last fifteen to twenty minutes are one long crowning moment of heartwarming.