People are afraid to write with a red pen, which has been an established tradition for thousands of years. It is taboo to write with a red pen, and it is even more taboo to accept what is written with a red pen.

Relevant evidence: 1, there is a folk saying that "Dan Shu is ominous". As we all know, in ancient times, except for the emperor sitting in the golden palace, calligraphy was generally used by yamen to record the names of criminals. There is a saying among the people that Yan Yan crossed out the book of life and death with calligraphy, and those who crossed it out with calligraphy were undoubtedly sentenced to death. Up to now, criminals who have been sentenced to death have marked their names with an "X" or "√" in red ink. 2. Because some people feel guilty because they write with a red pen, which leads to friends breaking up, there is also a saying that writing with a red pen is breaking up.