One of the highlights of Usher's OMG tour is when he selects a lucky audience member to come on stage for a serenade. Not any more. Watch this woman who accidentally kick the singer in his face with her heel!

Sure, the footage is a bad-quality fan video from a concert, but it's still as gratifying as a "fail video" gets.

By now we're well-aware of his love of grinding on inanimate objects, so do you think he kind of liked getting hit in the face with a shoe? Just some food for thought...