Some instructors are better than others, but let's assume you aren't wasting your time with bad trainers. When you go to a class, are you listening to what you are being asked to do? Do you pay attention to alignment cues in yoga? Do you check your form in weight training?
Listen to what the people in spandex wearing microphones are saying. They are certified experts who take continuing education classes and spend hours creating quality workouts. They have taken on the burden of exercise selection, interval timing, choreography, and sequencing.
Sometimes the key to success is recognizing that you can't get there on your own. You wouldn't ask an accountant to do your taxes and then scribble all over the return as she was filling it out would you? Trust your instructors. They want to get you there as badly as you do.
