My favorite part of training is seeing a client make progress towards his/her fitness goals. I keep a record of every workout that I have my clients perform and how well they perform it. This, in addition to observing changes in the clients stamina, exercise form, flexibility, etc., gives me a good idea of how they're progressing. It's fun to look back with some of my longer-running clients and see just how far they've come. It is a great feeling when someone that I'm training tells me how much better they feel since they began, or how their friends have noticed improvements.