What are the common superstitions and cultural taboos in Korea that foreigners should be aware of to avoid causing offense or confusion?

There are a handful of superstitions and taboos worth knowing so you do not accidentally cause an awkward moment. The most famous is the number four, which sounds like the word for death, so many buildings label the fourth floor 'F' in elevators or skip it, and gifts in sets of four are avoided. Writing someone's name in red ink is a taboo, since red was traditionally used for the names of the deceased, so use black or blue. Avoid sticking your chopsticks upright in a bowl of rice, because that resembles incense offered to the dead at an ancestral rite. There is also a widely known belief called 'fan death,' that sleeping in a sealed room with a fan running is harmful, which many Koreans grew up hearing even if younger people laugh it off.

Gift-wise, giving shoes to a partner is said to make them run away, and clocks or knives can carry unlucky connotations. On etiquette, give and receive things, especially with elders, using two hands or with one hand supporting the other arm, do not blow your nose loudly at the table, and take your shoes off when entering homes and many traditional restaurants. None of these are things people will harshly judge a foreigner for, but being aware of them shows respect and earns quiet appreciation.