There is a mantra I constantly hear from personal trainers and fitness pros: "clients don't want to know why, they just want you to tell them what to do."
This is some some serious bullshit.
If you work with a personal trainer and they are not telling you why they have selected the exercises you are doing, they are creating dependency. They are making it much more likely that if you stop working with them you will fail because you haven't learned anything except how to take orders.
You, prospective client, you need to ask why. Why this food and not that? Why this stretching, this cardio, this kind of movement and not that other thing? Without knowing why, once you stop paying that coach for one-on-one time, chances are damn good that you will back-peddle. Hardly anyone understands the practical application of calories in the human body, for example. Because of this, there is something like a 95% failure rate with dieting (Google "diet 95 failure rate" sometime).
My philosophy is simple: I emphasize the why. I expect you to engage and discuss, not pretend that I'm a drill Sargent on a power trip.
By the end of 2015, 75% of Americans will be overweight or obese. We didn't get this way because we are dumb or lazy. Not because we work on computers, play video games, read books, or build Legos. It's not because we spend time in cars, work too hard, smoke pot, or any other stupid fucking thing that some idiot says.
We got fat and sick because we stopped asking why. Why different types of foods behave differently in our bodies and what we should so about it. Why some types of exercises are great for our health, but not effective at burning body fat and what we should do about it. Why the "official" recommendations are what they are, if they apply to you and your goals, and what you should do about it.
We are not stupid. We are not incapable of taking care of ourselves. We just need to be told why and not just how.