Though late to the fandom, I am beginning to see where the nickname came from.

Few things have scared my neighbors as much lately as this lolarious KAT-TUN interview. In the sense that at about 0:55 I pretty much screamed with laughter. They're all talking about what they did last year that was meaningful, and then Jin flips his answer-board around and it just says "OBAMA" in big letters.

...oh, Jin. Don't let anyone ever tell you that you're not a winner. Because you are. ( Grade Awesome, A++++, Would Jin Again. )