Do not type chopsticks into cups

Top 12 in Top 12 Code of Conduct on Vietnamese dining tables.

Meals people are happily eating talk, accidentally knocking you into the bowl makes the atmosphere lose fun, but also shows what a minimum courtesy. You probably don't want to, but let's see why it is.
When you type chopsticks in the bowl, not to mention it is very unpolite and noisy, it also has another reason to call the soul, call the dead, very abstinence.