As Chu is downing shots at the last Sunday dinner, he spills some on the collar of his jacket. When he stands up to makes his announcement, the stain is gone.
When Madame Liang arrives by cab at her house together with her daughter and her grandchild, it is heavily raining, however, right in front of the taxi the road is wet, but there are no rain drops visible, in particular not in the puddle right in font of the cab.