It happens to the best of us. On Wednesday night, a shirtless Justin Bieber slipped and fell on stage while performing "Sorry" during the Kansas City stop on his Purpose Tour. The pop star took it in stride and went right on performing without missing a beat.It's not so shocking that Bieber slipped, seeing as the stage was covered in water from fake rain. The singer has made it rain in the literal sense on stage before, like at last November's AMAs . To be honest, we're just glad he wasn't electrocuted.