Vietnam is one of the country whose people use lunar calendar for their important days. For example, the date of Vietnamese New Year is on 1st, January in lunar calendar.
In the first three days, people used to visit family and friends, speak good words to one another, and worship ancestors. During these days, people shun to speak bad words or fighting as a taboo, because they believe those things will cause a unlucky life for whole year.
However, the most intestesting custom, in my opinion, is about Xông Nhà
. This is a person who be invited as the first visitor to visit a family's home. People believe this first visitor will decide the whole year fortune for their family, so it makes the candidate selection carefully.