When I visited South Korea for the first time there are a lot of things I sought for an explanation, here it is:
1) Why you have to use your both hands while accepting something?
2) Why do Koreans always asking for the age?
3) Why you cannot pour your own drinks?
4) Why is it bad to place chopsticks on the top of the bowl?
5) Why number 4 is being avoided?
6) Why you cannot write in red ink?
7) Why do Koreans always like shouting to each other?
8) Why some Koreans are usually using their middle fingers?
9) Why is it bad to give a "tip" in a restaurant?
10) Why you cannot give liquor to a woman, as a gift?