I'd direct Roar by Katy Perry with this plot, where she plays a 18 year old.
Initial scene: Katy's boyfriend's just left her and he's getting ready to leave. As he leaves, Katy desperately tries to make him stay, but there's nothing to do. She sits on her bed, looks at pictures of him on her phone, looks through the wardrobe to see the things he had left and as the chorus starts she stands on the bed and starts singing as sparks surround her; she goes on on her room's balcony.
Second verse: Katy is shown partying and dating a new guy and just living life happily.
Bridge: As she's walking through the school's corridors, she sees her ex and screams 'ROAR! ROAR! ROAR! ROAR! ROOOOOOOOOOOOOOOOOOOOOOOOOAR!' until he's pushed into a locker that says "dumbass"

Third chorus: Katy is shown in front of the whole school during a speech and walking through the corridors all happy and triumphant

End: An adult Katy is shown leaving her own business and grabbing an expensive car's keys, while, as she leaves the building, her ex is shown cleaning her office
That'd be the best thing ever
