What song should my next fanfic be based off of?

• Why Don't You Call Me Yet - http://www.youtube.com/watch?v=u-qLDd7J_h8
• Just Be Friends - http://www.youtube.com/watch?v=Jl_aUhZtKyg
• Kokoro - http://www.youtube.com/watch?v=McFKLwDALrM
• Servant of Evil - http://www.youtube.com/watch?v=658UHSIYyns