Emotion.
Music the the closest thing to real magic we have.
Edit: that said, some people have… weird facial tics when playing that are distracting, and sometimes disturbing. Two guys on YouTube who review gear, and stuff, who I won’t name, seem like really nice guys, guys you’d want to hang and play with. But, one chews his tongue the entire time, and the other stares stone faced like a robot into the camera the entire time. The latter has worked on that after people mentioned it, and is much better about it.
To be clear, I’m not mocking them. Like I said, they seem like really cool dudes. But that kind of thing can take all of your attention, instead of listening to the playing.
On the same tangent, there was a band called Flyleaf that had a minor hit in 2005 called “All Around Me.”
In the video, the bass player is hopping around like he’s high on crack the entire video. It’s extremely distracting. The director should have nailed his feet to the floor.