There's a few major areas that people seem to fail at most.
The first major one is being sedentary. Not moving and taxing your body will surely get you nowhere. You have to constantly do things in your life to make sure you're maintaining a healthy body. I don't mean be anorexic or have 0% body fat...I mean the real definition of healthy!
People never know what to do. This should be a clear sign that you need a personal trainer! Find one who works more to your style. If you can't find one at your club, find one somewhere else. If you can't open yourself up to your trainers, they won't be able to cater the workout to your specific needs. People are sooo much different from one another, and communication is the key.
People think faster and heavier is better for you. This is a cliche beyond all belief. Heavier weights are more for specific needs. Trust me when I say this...toned bodies and truly fit folks don't need to be ripped. You want to perform, not to look like a magazine model. Looking good doesn't make you a better person. Feeling like you can do anything and everything will improve your life drastically. There's a way to achieve both performance and looks, but it takes a serious amount of discipline and effort to do so. Don't let that discourage you!
Boredom or a lack of progress is a huge killer for people. You need to change your routines to cause muscle confusion so plateaus never happen. Doing so will not only give you more fun in your workouts, from changing routines so much, but it will also make your muscles grow.
If you're ever thinking about ending your gym membership, just remember that fit bodies are earned and then maintained. You do NOT get fit and then just magically keep it. You have to constantly work at it to keep it there. Never give up on it unless you absolutely have to for other reasons...life is great, but it will always be better when you're at your healthiest.
