I like BoA as a dancer. The first video I saw from her was "Eat You Up": I'm a fan of hip-hop dance, so I liked her immediately. Funnily enough, it was actually hip-hop dance that got me into K-pop in the first place (via Taeyang, from Big Bang).
But Nell are probably my favourite Korean band. There's a song of theirs called "The Day Before" (video) which is so ... sad.
My favourite of theirs, for sure.
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It is easy to go down into Hell;
Night and day, the gates of dark Death stand wide;
But to climb back again, to retrace one's steps to the upper air –
There's the rub, the task.
– Virgil, The Aeneid (Book VI)