It’s been established that hints for the next album are interspersed throughout this album, thus…
There’s something very interesting in the lyrics. Jonghyun says that women are sensitive creatures, and need to be sweet-talked, but then Onew interrupts again, saying that playing the piano is the only way for the girl to take interest in a guy. He obviously already stated that before, but he emphasized it again. From beginning to end he kept on emphasizing playing the piano.
…so perhaps there’s a very centred piano song in the next album?