It was a total shocker that Iggy Azalea wound up on one of the smaller stages at ACL Fest, if only because the crowd that came to forget their "Problem" for a sec turned out to be the size of multiple football fields. When your biggest hits ("Fancy;" "Problem") are collaborations and can't be performed full-out without the cohorts on the track, it can be a tricky let-down, but Iggy plowed through rousing in-tandem renditions of "Problem" and "Black Widow" (even if Rita Ora didn't show up ready to roll some heads with a samurai sword in hand).