That's very very very true.

One thing I would be hyper-attentive to is instruction that *starts* gently, and then shows more advanced yogi how to progress - not a teacher who starts with a classical pose and *then* gives modifications to beginners or people with injuries, less flexibility, etc.

There was one teacher in particular at my studio that I learned I just could not do his class. He would give lip service to only doing what you can and not getting hurt, but he would START in a fairly tough place and invite people to back off if they needed to. I never felt I needed to ... until I came out of the pose with a muscle strain. Like, every single time I did his class.