You're not allowed to stab your chopsticks vertically because this kind of like, replicates when you're like, at a funeral, trying to pay respect for someone, they normally like, put incense into soil and stuff so that's, like, the whole idea of it.
不能把筷子插在食物上,因為這看起來有點像在喪禮,當你想要表達你的敬意時人們會插香在土裡之類的,大概是這樣的概念。