I start back in 2008 with TVXQ/DBSK.
I tought they was japanese. I discover them as Tohoshinki because I was fan of Johnnys. At first, I was kind a “anti” because everyone said that they are better than Johnnys and belittle my fav. But after heard a lot of them, I try them (my first song of them was Why did I fall in love with you?) and I found their voices really pretty and they was better in dancing and more funny than Johnnys, so I became their fan. And after learn they was Koreans, I listened theirs korean songs and others Kpop groups (Super Junior, SHINee,…).
In fact, I’m not really on Kpop now but I’m a hardcore fan of DB5K (all members of TVXQ) and my bias is Kim Jaejoong.
I already saw TVXQ and JYJ in show, but I would love see them together. I don’t give up the hope~
TVXQ acapella for the occasion 
https://www.youtube.com/watch?v=4PvakSTs8Lw
TVXQ do a cover of Lion Heart (Smap song)
https://www.youtube.com/watch?v=wn_p5qMrtiE
Compilation of good songs of TVXQ (they are so perfect… I don’t even know HOW is possible to don’t love them)
https://www.youtube.com/watch?v=orb7eXT6Rrg
Btw, we already have a subject about it: How did you get into Kpop?