Since when has it been de rigeur to like the star you're watching at a concert? Lady Gaga's Little Monsters do it. At Glee: Live, people were wearing cheer outfits and letter jackets. And at Katy Perry, blue wigs abounded. Really, it's not enough to wear jeans and a shirt to a show anymore. Chalk it up to the list of things you can blame on the Internet: Everything is so interactive these days, it's not enough to go to a show, you have to be PART of the show.
Here are our top WTF costumes from last night's Katy Perry show at Nokia Theatre.