Siwon always calls Eunhyuk by a different name.  Eunhyuk was starting to get annoyed at this until it was explained to him that Siwon had some sort of psychologic issue with remembering names.  Siwon can only seem to remember names if the person is important  such as those names in history textbooks and famous celebrities or if the person was someone he spends a lot of time with such as family and close friends.

Eunhyuk wondered how long would it take for Siwon to be able to get his name right.