A video currently appearing all over the place has us seeing a completely new side to Darth Vader and his Storm Troopers.
Maybe this is the reason why he wanted to crush the rebel, they simply couldn't groove like him and his boys. Just think all those lives could have been saved if the rebels had only just accepted the Dance-Off invitation. All those generals that Vader killed also must have miss-stepped more times that Vader liked, ever notice how he never kills the Storm Troopers? That's why. They know how to hit the beat.