City Brights' Yumi Wilson reminds us with Yoga: Pleasure ... and pain that a drill sargeant is not needed to lead a yoga class:

Over the years, I've tried my hand at a variety of styles of yoga. In the '90s, I devoted myself to Bikram and returned periodically when I sought the need to stretch and sauna at the same time. In the first decade of 2000, I tried Hatha and Ashtanga or a combination thereof, hoping to calm my busy mind and loosen the tightness around my right hip. But each time I take a class, I am always left with the same question: When did group yoga become the new form of Basic Training?

It's so easy for an instructor to overdo the emphasis on alignment and perfection until it alienates students into avoiding the classes all together. You see so many students start out with the Fundamentals class for six or eight weeks, and then when they have to make the transition to a regular class, the sudden increase in just turns them off completely to yoga practice. Thrive Yoga, for instance, does a solid business with Fundamentals I and II, but I can't see that many of these students can make the transition to regular practice. Some will make it to the Hatha Yoga classes, but a vinyasa flow class is a "bridge too far." I think Thrive's teachers are not exceptionally overwhelming in their instruction style; if anything, they are adaptive to the skill level of each student. But it's so easy to make assumptions about ability based on one's own competence in practice. If students come out of the class feeling failure, rather than savoring the rewards of yoga no matter their skill level, then it's just going to make it more difficult to come back for another class.