Sit Back And Enjoy!!! Some of this stuff may be opiniated but come from reliable sources. (I have a friend from Korea and I asked him to help me with this card XD)
Sneezing/Coughing- So people in Korea don't cover their mouths. Children are kinda learning to but the older people don't. If u don't like germs then this may be a problem.
Bus Drivers- In Korea most people walk everywhere. U can get a car but that's on you. Umm bus drivers will not always stop to let you on and off. They will slow down but won't completely stop. And it'll happen to anyone even elderly. The bus designs are really weird. Sometimes they'll only be up to 8 seats!!
Public Restrooms in Korea- Okay so in Korea they don't flush toilet paper. They have a wastebasket literally in the stall where u put USED toilet paper and they hardly dump it. And with traditional Korean toilets where u have to bend ur knees and kneel down its not a good combination.
No Manners?- There are no words/phrases for Excuse Me or anything like that that Koreans use hardly. They can be very aggressive and are know to push/elbow you to get to where they are going. But they try to be polite with it if that makes sense lol.
Taxis- Since taxi drivers are cheap, especially in Seoul, they are used a lot. But that doesn't mean they're the best way to go. They will not listen to you. In Seoul the taxi drivers are so bold. They will treat you like you don't know where you are going. Just make sure u know where u are and where ur going bc they will try to pull one over on you.
You Will Be An Oddity- You will get stared and pointed at. People will shout loudly and point out ur a foreigner. Salespeople wont want to help because they'll think you'll force them to talk English. Its ridiculous lol.
Oldest Pays Always- There is no splitting the bill. It is customary for the oldest to pay all the costs for everything when you go out. There's also no tipping. Koreans take that as you bragging about ur wealth.