Any coach worth their salt knows the value of fundamentals. No matter how advanced an athlete is, going back to the basics from time to time to continuously improve technique can never hurt. More often than not, people find that areas they'd once had a firm handle on need a bit of honing, whether that's due to injury, bad habits or something else entirely.
Perhaps at least peripherally related to the value people attribute to constantly improving fundamental movements, a favorite past-time of athletes and coaches alike is to watch embarrassingly bad videos on YouTube and comment on the lack of technique, poor coaching, and so forth. And yet few seem to pay as much attention to the fundamentals of one of the most crucial aspects of coaching--the way you treat your clients and the culture you create in your gym.

I do believe that people who fall into bad habits are fundamentally good people who need a course correction from time to time. But just like poor coaching can hurt someone's technique, failing to act respectfully can have a negative impact on people's lives (and make you look like a douchebag, no matter who you are on the inside). So if you find yourself slipping into the habits mentioned below, consider this post a wake-up call.

Your coaching

1. Show up. This should go without saying, but showing up late or leaving early on a regular basis makes it pretty obvious where your priorities are. So does repeatedly canceling or rescheduling.
2. Learn people's names. Not good with names? Make flashcards with photos of your members. Look over the list of clients coming to you for personal training before they come in. Read books on word association. Figure it out. (Yes, you get bonus points for remembering how to pronounce difficult names.)
3. Pay attention to the people you're helping. If you're bored and annoyed while coaching people on a regular basis, perhaps you're in the wrong profession. Find a way to make things more interesting, or change something else. Coasting is not enough. Paying attention to your clients also means that you help everyone in the room during a group class, not just your favorite people. (Everyone at your gym should be getting incrementally better, though of course the amount of improvement will vary.) And there's no excuse for stopping a training session to have a prolonged conversation with your long lost friend who just walked in while people are waiting for instruction.
4. People can tell when you're not invested. If you think you can fake being interested with your clients, you're wrong. Obviously there are certain times and situations where it may be difficult to focus on the task at hand, and people may well be desperate enough to turn their lives around that they'll take anything they can get), but even just viewing people in a dismissive way leaks into their training. It's inevitable.
5.  If you can only coach super fit people, then just do that. Far better than pretending you want to help everyone and coasting through it. Just remember that even your high-level athletes may need help with fundamentals from time to time, be dealing with injuries, and may even have trouble complying with their regimen.

Your attitude

1. Nobody cares about your striations. Bragging about how fit or strong or sexy you are, or talking smack about all the unhealthy people you see may initially get you some high fives, but it's also going to make it a lot less likely that people will send clients your way. Would you feel comfortable against someone bragging about a skill you have yet to attain and criticizing people at your level? You may not always see the path of referrals or know who notices what, but treating people (even those who won't become clients) with a basic modicum of respect is a good start.
2. People read your Facebook posts and Twitter feed. If you really think you can compartmentalize your coaching in the gym and keep it separate from your online persona, welcome to the Information Age and open up them eyes.
3.  You may know a lot, but you don't know everything. Make sure to really listen, and get information instead of just giving it. You'll want to closely modulate in certain cases, but it's hard to know how if you don't even pay attention to what's going on.
4. Remember that people have more going on in their lives than just your gym. It's easy to forget that you've centered your life around fitness and that desk jockeys find a healthy lifestyle considerably more difficult. There are many other factors at play. Being overweight doesn't mean people haven't already dropped large amounts of weight (and often they have a thyroid problem, or other issues). There are also psychological reasons that some people gain weight after traumatic life events. And then there are financial issues and the lack of access to fresh food. This isn't to say that all of these factors can't be overcome--just that they should help temper your rush to judgment.
5. Taking time off, or not working with you, doesn't mean that someone's not exercising. You also can't peer into men's hearts and know whether or not they're trying to change. Having a lot more compassion can ultimately effect more change than rushing to judgment.

Bottom line

Spoken word artist Jefferson Bethke once said that the church isn't a museum for good people, but a hospital for the broken. This article isn't about religion. I do, however, see the gym the same way. In fact, I'd go so far as to say that a coach making fun of an out-of-shape person at the gym is equivalent to a doctor making fun of a sick person in a hospital. If you've ever seen a coach display obvious contempt for the very same people they're supposedly trying to help, set a different example. Do better.