The inner joy apparent in the video is absolutely from the programers themselves, not the robots. This is a programmed sequence. This video makes me smile every time because to me, it is a bunch of geeks using the robots as an artistic medium to express themselves, as any artist does in other mediums. Boston Dynamic robots can problem solve to the extent that they can traverse difficult terrain, open doors, crouch, etc, when told to get from point A to point B, but responding to music is not in the AI.
I don't fear these inquisitive, creative scientific minds, what I fear is that every time some wonderful invention comes along, some evil **** comes along afterwards and turns it to pure profit or even direct destructiveness.