The other day I had just wrapped up a session at the gym. For my strength training I do circuit training that is designed to increase power to weight or muscular endurance depending on the routine. I typically look like I've been hit with a fire-hose at the end and I'm pretty nuked by some of the work-outs. These are not base-fitness building Zone 1 endurance sessions which I do outside mostly - running, biking, stairs, etc.
In the locker room a guy strikes up a conversation. I've seen him coming and going to the gym for years, and he's still easily 80-100lbs overweight and still has droopy shoulders, no visible musculature, and gets winded just getting dressed post-work-out. He's preparing a protein shake and asks me what my secret is to staying so lean - he can't seem to make any progress. I'm occasionally asked this, and I usually take the politically correct way out and the conversation is over quickly. But today I figure I should let him know the truth.
"You're wasting your time at the gym. I've seen you working out, and you're accomplishing nothing. You're spending your time wandering around, maybe checking out the gals, who knows what, but you're just coasting around the floor doing nothing. Your cardio warm-up is short and really accomplishes nothing. Your weight routine is nether building strength nor endurance, you're just moving too little weight around for too few reps or sets, and then you have these huge rest periods despite the low effort. When you're moving to the next machine you move slowly wasting more time. At first I figured that at least you weren't sitting down eating Doritos and then I see you mixing up that 500cal shake that you don't need at all. I've worked with sports nutritionists that consult to Olympic athletes and none of them use those shakes. They're only for body-builders that are using an unbalanced diet to build huge size - everyone else can easily source the protein they need from their diet. It's just a bunch of calories. Keep a food log and restrict your caloric intake and up your cardio to begin losing weight. Add in weight training but learn to do it properly so you stop accomplishing nothing and add in body weight exercises like squats and lunges and push-ups that engage multiple muscles. Core strength is vital and work on balance. If you have to sit down to put on your pants, you're weak and your balance is terrible. I know you're willing to invest the time - you're here a lot. Just start making all that time count."
This applies to at least half the people I see at the gym. They invest a lot of time, but little else. Make it count.