What does that mean exactly? It means that a great class involves an exchange of energy between an instructor and participants. Class participants also are responsible for creating a great class. It's not just a one way relationship. Participants affect each other as well and the attitudes of participants will affect the instructor.
Today I was teaching my regular noon class. Maybe it was the shit weather this week. Or maybe it was just the fact many people were there because they knew they would feel better after it was over, but not so much during. I had this moment of "ok guys. I need your help. I can't do this alone. Can we try to work together to build some energy in the room and help each other through this?" And it worked.
I've noticed the energy in class environments for YEARS!. I started teaching back in 1991. In fact, today Leslie gave me an old VHS tape of one of Jane Fonda's original vids. Yes, I dressed like that. Yikes.
Ever wonder why you love some group classes and not others? It might not be the exact type of music you like. You might not like all the exercises you're being forced to do. But there's something that happens in a room when a great instructor manages the relationships in the room. Not only does a great instructor have to know their stuff, they also have to manage energetic issues in the room (ie. people who chat too much or become black holes of negative whiny energy). The focus of an instructor needs to be divided between excellent form technique and class design, but also in keeping everyone in the room together as a unified team or group.
So next time you're in a class you LOVE, take a second and see if this excellent instructor is managing the relationships in the room or merely standing at the front and demonstrating. It takes an assertive personality to keep everyone focused on the greater good of everyone.
And when you find an instructor like that, you will follow them anywhere.