I've been living in Vietnam for almost a year, and there is a crazy amount of superstitions here. Some of them are eastern Asian, and some were proudly invented here.
- Number 4 is an unlucky number. 6 and 8 are lucky numbers. In fact, most wifi passwords here are 66668888 or 88888888.
- Don't stick the chopsticks in rice in the middle.
- Don't flip the fish as it mimics the fisherman's boat flipping.
- Burn a ton of stuff to help the diseased at Tet holiday.
This is common in the West [1], I do it, probably picked up from the Chinese around tea. I've also seen ice nerds talking about it in a positive way.
My conspiracy is when you have dirty water any memes that encourage boiling more water will proliferate. (Since you'll drink the old boiled water over collecting more from a stream)
For that 4th bullet, did you mean "hóa vàng"? I think the paper stuff that's burned symbolizes things that will be carried to the afterlife - where their ancestors/dead loved ones currently are. This is why you may find many modern objects like phones, cars or even houses in small paper forms ready to be hóa vàng-ed.
i'm not any kind of Asian but I believe #2, chopsticks sticking out of your rice, is rooted in a belief that it resembles the incense burners that would be set up at a funeral - a sort of bad luck charm.
- Number 4 is an unlucky number. 6 and 8 are lucky numbers. In fact, most wifi passwords here are 66668888 or 88888888.
- Don't stick the chopsticks in rice in the middle.
- Don't flip the fish as it mimics the fisherman's boat flipping.
- Burn a ton of stuff to help the diseased at Tet holiday.
- Don't boil the same water more than once.