When you're weightlifting at the gym, you're not just working out for yourself; you're putting on a show for everyone around you. Each weightlifter is like an actor in a play. If all the actors know their lines, the play runs smoothly — but if just one actor doesn't play his part, the performance quickly becomes chaos. 

In case you haven't had a chance to rehearse your lines, here are the "Eight Worst Things You Can Do at the Gym".

Number 1: If someone is using a machine you want to use, don't stare them down until they get off

There is no worse way to kill the movement of a scene.

Someone is always breaking this rule at the gym. You'll be in the middle of a set of preacher curls and you'll notice some guy is standing behind you with a zombie-like expression on his face. It's creepy. It's no way to ask someone to borrow something.

If you acted that way in the real world, you'd be considered a lunatic. The gym is no different. No one wants to disturb other weightlifters, but it's better to ask then to hover. Such impish behavior can agitate weightlifters and will brand you as a scared amateur. 

What to Do: If you want to use equipment someone else is using, wait until he or she is done with a set and then ask how many sets they have left and if you can work-in with them. This won't annoy weightlifters. If the answer is no, just move on to another exercise; there's more than enough equipment in the gym so that you don't have to hover over one poor guy until he's done with his set.

Number 2: Don't drop the dumbbells when you're done with your set

It's like an actor throwing a prop to the ground, when the stage direction says "place gently."

Many people finish a set of dumbbell presses by throwing their weights to the ground with a thunderous clang. It's a way of flexing and releasing the tension in their muscles — but have you ever spotted a friend on dumbbell press when they drop the weights? Look around and you'll see everyone in the gym staring at you with their necks wrenched in your direction like they've heard a crack of thunder.

Dropping dumbbells is an annoying habit that distracts other weightlifters and damages the weights. It doesn't look tough; it looks foolish. The last thing weightlifters want is that kind of disruption from their routines. Even worse, repeated dropping of dumbbells can weaken the weights by loosening the plates and bending the bar.

What to Do: Though it may be difficult, bring the dumbbells slowly to your body and then rest them on the floor. Have your spotter lift the weights from you when you're done. If you're doing curls, under no circumstances should you drop the weights. If you can't rack the weight you're curling, you're curling too much weight.

Number 3: Don't do an exercise in front of the weight rack

The area in front of the dumbbell rack is center stage, the place every actor wants to be — but not every actor should be crowding the spotlight.

Too often, weightlifters pick their dumbbells off the rack and begin pumping iron right there, obstructing the weight rack. You've seen the guy at the gym that stands right in front of the rack and does thirty reps of curls per arm while blocking half of the weight rack. Isn't it amazing how he seems completely oblivious to the weightlifters that circle him like sharks waiting to get their hands on the proper dumbbell?

The area right in front of the weight rack is a high traffic area of the gym. Weightlifters are constantly up by the rack picking up dumbbells. Weightlifters who exercise in front of the rack not only block other lifters from grabbing weights, but also risk injuring others as they swing their weights. You're likely to be clipped if you try to sneak up to the rack in front of an inconsiderate weightlifter.

What to Do: This is easy to prevent. Just have the presence of mind to take five or six steps back from the rack before you begin your exercise. Sure, you want to get a good view of yourself in the mirror, but that's just something you'll need to learn to give up.

Number 4: Don't lift more weight than you're capable of lifting

Like Arnold Schwarzenegger playing an accountant, trying to lift more weight than you're capable of lifting is out of character. 

There is no amount of weight you can bench press that will make you look larger than you are. This is equally true for the 150 pound guy trying to bench 300 pounds and the 250 pound girl trying to bench 500 pounds. A message for both of these people: you aren't fooling anyone. You know the middle-aged man with a small build, who tries to bench two times his weight and ends up with the bar flat on his chest and four guys running to his aid? Don't be that man.

Struggling with more weight than you can handle is dangerous for yourself and for those around you. If you're lucky, you won't be hurt, but it's more likely you'll bust your sternum or tear your pectoral muscle. Doing more weight is no way to make up for work-out time missed.

What to Do: Be reasonable! You should know your own strength, and if you don't, start at a low weight and work up to it. You'll never get bigger if you're lifting the improper weight and you won't impress anyone.

Number 5: Don't wear the wrong gym gear

Costume design in the gym? It doesn't have to be Chicago, but it doesn't have to be Rent either.

The gym is a dirty place. It's a place where you can wear the same clothes every time you're there. It is not a place to play dress up. Have you got the freshest new sneakers? Leave them at home. Headbands and wristbands? Take them off. The gym is probably the only place on earth where you'll look good wearing an old t-shirt and some tear-away warm-up pants.

Of course, don't wear clothes that make you look too stupid either. Oversized tank tops should not just stay at home, they should stay in the discount bin at Wal-mart where they belong. There's nothing wrong with wearing the same shirt to the gym every time you go. Think of it as your uniform. But, make sure your uniform doesn't look stupid. You don't want to be the guy at the gym always wearing a miniature tank-top or the same Hard Rock Café t-shirt. 

What to Do: Wear something that's comfortable and that you wouldn't mind getting dirty. A plain white t-shirt or snug black tank-top works just fine.

Number 6: Don't lean on a machine you're not using

Just as one actor shouldn't speak over another actor's lines, weightlifters shouldn't interrupt someone else's workout by leaning against a machine they're not using.

Some people see going to the gym as a social event. You may run in to a few jesters at your gym who don't want to do anything but lean against the leg press and talk. They'll spend an hour and a half at the gym chatting each others' ears off while they lean against the leg press blocking everyone else from using it. You need to be careful who you offend at the gym, though, because when a 250 pound steroid enhanced titan of lean muscle wants to work out his legs, he will work out his legs.

When you're working out, it's natural to get tired and rest for a minute on a machine you're not using. What you're probably not thinking about is that other people are waiting to use that machine, and while you're sitting there, they're getting mad.

What to Do: Be conscientious. It's easy to lean or sit on a machine without realizing that someone else wants to use it. Once you're aware that simply touching a piece of equipment means that someone else won't use it without asking you, make sure you find a place you can go to relax when you're tired. Instead of sitting on a bench press bench, go out in the hall and find a real bench.

Number 7: Don't scream

Caesar was probably not cracking up when he uttered the words, "Et tu Brute?" He more likely whispered them with defeat. How do you deliver your lines?

The gym is not a horror movie; there should be no bloodcurdling shrieks of terror. The ab-roller is not that frightening. That said, it's natural to feel the urge to scream when you're struggling through an exercise. Sometimes you just can't keep it bottled inside and have to let it out. That's alright if it's done reasonably, but not if it's bellowed like a banshee.

When you're working out you'll probably come across a few 'Wildmen.' 'Wildmen are usually big with full beards. When 'Wildmen' do leg squats they scream like wounded animals for every one of their fifteen repetitions. It's a paralyzing scream that will frighten lifters into dropping their weights. 'Wildmen' will scream so loud that it is impossible not to turn and look at them. But when you do stare, a 'Wildman' will glare back at you with canines showing, daring you to turn your glance to towards the ground.

What to Do: Unless you work out at a kennel, keep the barking to a minimum. Everyone screams when they're forcing themselves through the last couple reps. Just keep the decibels reasonable.

Number 8: Don't talk on your cell phone at the gym

A ringing cell phone is never in the script.

This is as true in the gym as it is in a movie theater, a restaurant, or in church: don't talk on your cell phone. Remember, the gym is a play. Before you come to the play make sure to turn your cell phone off if you bring it at all. And why would anyone need to bring their cell phone into the gym with them? Unless you're a doctor, there's no need to be on call.

It may seem silly — what, with the grunting, metal clanging, and rock music blaring — that the ring of a cell phone would upset weightlifters. Well, maybe there's just something annoying about hearing a digitalized version of Ode to Joy, no matter where you are. 

What to Do: If you're expecting a call that's that important, don't go to the gym. 

You know all the best exercises, you know how to keep a training log, and now you know the unspoken errors that weightlifters make. If you're wise and avoid these mistakes, you'll make your gym experience — and that of everyone around you — a lot less aggravating. Plus, you can shake your head in shame when you see others break these rules. Most importantly, be aware that when you're at the gym you're part of one big play. It's impossible to separate what you're doing from what everyone else is doing. Just try not to forget your lines.