You've undoubtedly seen the video by now, but just in case you haven't, take a look at Green Day frontman Billie Joe Armstrong losing his mind at a recent show in Las Vegas:.

To the untrained eye, that might look like the greatest act of rock and roll rebellion since Kurt Cobain wore a dress on Headbanger's Ball. But the truth is, it's the exact opposite. What you're seeing is one of the saddest, least punk rock moments in rock history. Here's why ...