For a long time, I couldn't figure out what that instru riff in "Teenage Dream" reminded me of (the part that starts quiet in verses, then really loud in chorus ("Dah...DAH dah dah") All of a sudden this morning it hit me...it's very similar to the instru riff of verses of "When It All Falls Apart" (The Veronicas).....maybe it was an inspiration? http://www.youtube.com/watch?v=X02GKrexDAs
yeah is true , it's very semble , the veronicas song is amazing.