My informant is a student who was originally from China but came to study in US since high school.
“In China we are not allowed to place our chopsticks perpendicularly into rice bowl while eating. It is very inappropriate to do that there, because it would look like you are worshiping dead people.”
This is a common habit that parents always forbid their kids to do on the dining table since their very young age from decades to decades. My informant says that she still keeps that rule in mind every time she eats with chopsticks now, even though she no longer thinks about the reason behind it anymore.
It is quite interesting to me that there are many homeopathic folk beliefs like this in Chinese customs, which I think more or less relates to their hieroglyphic language that allows them to randomly connect two things that share similar features together.