Radiohead wrapped their brief 2009 European summer tour at the Reading Festival in England. They weren't really supporting a new album at this point, giving them space to reach back into their catalog to guaranteed crowd-pleasers "Karma Police," "Exit Music (for A Film)" and "Street Spirit." None of those were too shocking, but most people were pretty stunned when the band walked onstage and busted out "Creep" as the very first song.
They had revived their 1993 breakthrough single a bunch of times on that tour, but it almost always came near the end of the set. It's unclear why exactly they played it first at Reading, but it meant the one guy who usually screams "CREEP!" after every song at every Radiohead concert would shut up, or at least yell for "The Bends" or "Fake Plastic Trees" instead. (That same guy yells for "Hurricane" at every Bob Dylan show and "Southern Man" at every Neil Young concert. He is the worst person in the world.)
Thom Yorke has complex feelings about "Creep." The success of that song completely changed his life, and it's quite possible that Radiohead never would have taken off had they not written that track, but there was a good four-year period where it was the only Radiohead song the mass public knew. Radiohead's 1995 song "My Iron Lung" is about the realization that the very thing that's keeping you alive is also trapping you in a very small space.
Radiohead largely dropped the song towards the end of the OK Computer world tour, bringing it back periodically in the 2000s. It always made the crowd go insane. This performance at Reading in August of 2009 is the last time they played it, even though they spent most of 2012 on a grueling world tour.