What is the most difficult thing in Seoul?

I’m always curious about one question.

What is the most difficult thing as a foreigner or traveler in Seoul? What kind of information do you want to know about or what kind of service do you need to live in Seoul? Otherwise what make you happy or joyful during your holidays in Seoul.

If you have any exprience to travel or live in Seoul, please leave a comment for this question? Or you if you are planning to visit Seoul, what do you want to do for the first time when you arrive here. Maybe you are not interested in travel agency’s boring program and do something new for your precious holiday in Seoul.

Let me know your opinion and experience about Seoul or Korea. I want to know about what is not enough for traveling in Seoul.