I know this has been done before, but I just wanted to share my top 6 list.
Partial Rep Pros i.e. Ego Super Stars - People who NEVER use full range of motion. You're not that strong; you can't bench 315 to depth and if you do, you bounce it off your chest and then have your spotter curl the bar off of you.
The C.A.B. Crew - You get to the gym, do a set of Curls, a set of Abs a set of Bench and call it a day.
Cardio Addicts - People that ONLY do cardio because according to them, if they even LOOK at a weight wrong, they'll explode and become the next Mr or Ms. Olympia. Oh and of course, doing cardio is the most effective way to lose fat, duh.
Ostrich Syndrome - You look like you lift weights at first glance, but that's only because you've been part of the C.A.B. crew for the past 10 years and successfully created an optical illusion. If someone told you to squat or do one of it's variations, you would tell them you would, but it's bad for your knees. You prefer to train your legs on the elliptical or recumbent bike while reading GQ Magazine.
The Belted Warrior - Why are you wearing a belt during your set of curls? If you're using your back THAT much, you're probably not strong enough to use that weight.
The Etiquette Challenged - Yes, I'm still using that piece of equipment, my belt and water bottle are 1 inch from it and my sweat is still on it. Yes, I'm planning to use that 45 lbs plate, please don't take it off during the MIDDLE of my set. Go get that one from the Smith Machine that's 3 feet away. Why wouldn't you do that in the first place? No one is on it! You want to know how many sets of squats I still have left in the rack? Quite a few, why what are you planning to do? Curls and Pullups?! Here's a tip, if you can pick the bar up off the ground, you don't need the rack! There's also 6 other stations you can use that are SPECIFICALLY BUILT for pullups!!! Please put your weights away when you're done, consider it part of your workout.