I don't know why people keep blaming things on Lee Soo Man. Why can't y'all differentiate voices? They didn't choose Krystal to sing for this song because they "liked" her more than Luna. Luna's voice is amazing, yes, but her voice is too powerful for this. Krystal has a sweeter (and sharper) voice, that's why it's more suitable for her to sing this song instead of Luna. Luna's powerhouse voice and singing techniques would take away the desired pitch for this song. Calling yourself an f(x) fan without even knowing what kind of voice your idols have is shameful. I'm standing by this, don't even think about arguing. Also, whatever happens behind the screens does not concern anybody nor the fans. Don't stir up unnecessary things. Even if they fight, it's their problem, not ours. Y'all needa calm down and take what you're given, shut up and watch what you're shown. Your bias is not "yours", they're working. As entertainers, they're already stressed more than any human being should be, so if you love your biases, stop creating extra issues for them. I hate to see how tired Krystal looks. Babygirl needs a break, even a short one would be good.