Judging by the cover art for Katy Perry's "The One That Got Away" and the lyrics to the same, she's nostalgic for one of two things: that year or so last decade where everyone from P!nk and Gwen Stefani on was sporting pink hair (jeez, Katy, haven't you heard the nostalgia cycle's still in the '90s?), or that time she was on the cover of InStyle with the hair color. She's staring into space, so you know she's pensive; she's doing so with lips parted, because she's Katy Perry. Pay careful attention to this stare, though. It is the stare that signals Katy's thoughts of breaking Michael Jackson's reign of No. 1 singles off Bad. (We know it's a bad coincidence of timing.)
There's also a radio edit, which sounds mostly the same as the original: big thumping Max Martin/Dr. Luke beats with a melody attached. It's worked for all the other Teenage Dream tracks, not to mention about half the charts; why not?