Living in a city like Seoul will be a special experience of your life and career.
It is actually not a geographically big city but there are tones of aspects that you can't even imagine.
Oriental life style, culture, architecture plus modern buildings and shops, sports complex etc..
Seoul never gets dark even in the late night.
Shops are mostly open until 2 to 3 AM (especially bars, pubs and bbq places).
Old and new things coexist and you can get everything you need(if you have money).
Once in a life time you should visit this city.
Early in the morning you wake up and go to Han river for a morning jogging.
And after you finish jogging, you go to a café for brunch and you spend a relaxed time there.
Later when you finish your brunch you move to see old palaces and gates in Seoul.
You will see how great the world best subway station system is.
When you are done watching the old palaces and gates, you move to see a old villages of Korea.
You take a coffee in a café or you can just take it out and walk around the village.
In the night, you see bright shops and bars at some hot places like Hongdae, Gangnam, Itaewon etc..
Eat great Korean style BBQ(samgyupsal) or soya beef(bulgogi) with Korean traditional liquor 'Makoli'
Sound so delicious.
You can drink all the night or you can move to dance in a big floor.
When you go back to your place, you can use night buses running until 5 AM.
Yes.
In Korea, you never get sleep.
(but it doesn't mean every Korean do not sleep. We go to work every morning. As you know we are very notorious about working hard)
As you are a tourist of this city, you never get down.
