I wanted to add one more thing from my experience. When I started as a trainer my boss/mentor was used to training athletes, and really believed that for a person to get their "money's worth" from a training session they needed to work HARD, and get the sum of my knowledge even in their first few sessions. He would look over and approve all of my programs before I met with my clients. Well, I found for the average out of shape population it just didn't work. At first I couldn't figure it out, I only saw each of my clients once and I never saw them at the club again. The point was driven home after I had been seeing a client for several weeks and was taking her through what was a tough workout for her. During the workout she started crying and left. Hmmm. She said she wanted results, said she was willing to work hard, and I knew in my heart she could finish the workout. What I hadn't counted on was she was so demotivated by not feeling successful at the workout that she wouldn't stick to it long enough to see results. So I took down the intensity of the workouts for my new clients and no longer tried to kill them. All of the sudden I had client retention and was able to get them to their goals because they felt capable of finishing the workouts and had that feeling of success. It is frustrating because during the interview everyone knows what they are "supposed" to say; I am willing to work hard, they all want results, and they all want it now. But in reality most of them perceive the breathlessness and muscle fatigue as a personal deficit. They don't have the experience to know that those signs mean they are being successful, they perceive them as being a failure. As they become more sophisticated exercisers you can bring the intensity level up to what you know they can complete and they will ultimately be motivated by this, but it takes a while to get there.
Hang in there, it takes a while to find your own personal training style and the training sweet spot where your clients will continue and still get results.
Shayne