Leave sweat on everything. Or hair product.
Grunt like you're giving birth as you squeeze out those last few reps. (Really. It's not manly. It shows everyone you suck at math. And it makes the rest of us nervous that you might be, like, pooping on the bench or something without even realizing it.)
Do a training circuit on multiple pieces of equipment and get mad when people have the gall to use "your" machines when you're not on them.
Wear little coordinated outfits. (There is a strong statistical causality between wearing little coordinated outfits and accomplishing nothing more than just being in the way. They … um … did a study.)
Wear layers and layers of baggy clothes and lots of bling, as though you just came from shooting a hip-hop video. (Ditto.)
Wear a sweatband just below your elbow. (That fad was over before it started. Unless you're a 12-year-old girl.)
Hold up your shirt and check out your abs in the mirror. (They haven't changed since you last checked them, slugger. And they may look ripped, but admiring yourself makes you look really desperate.)
Work out in a tank top that's so big your nipples show through the armholes and the waist is down by your knees. (We get it: You're built like a brick shithouse. But you look like you're wearing a sundress.)
Be completely unaware that your balls hang out when you do stretches in boxer shorts.
Call somebody a "faggot" loudly enough that other people can hear you. (You're not fooling anyone but yourself, cocksucker.)
Wear your steroid patch where everyone can see it. (Though I guess it saves us the trouble of having to sneak a peek in the locker room to see if you have really small testicles.)
Yell GOD DAMN IT! and slam locker doors when you discover someone else is using your favorite locker. (Dude, lay off the steroids. And why do you even have a favorite locker? It's kind of creepy.)
Masturbate in the shower with the curtain open.
Masturbate in the shower, period.
Don't shower for a couple days before your workout. (Save your pit-whiff for the back room at the Eagle, pigboy.)
Douse yourself in cologne or perfume before inducing a 45-minute sweat on the treadmill. (See those unused treadmills going wasted on either side of you? See those asphyxiated corpses littering the floor? That's because of you.)
Stand in front of the drinking fountain to read the sign over it without checking to see if there is a line of thirsty people behind you. (If you've ever done this, you suck and I hate you.)
Use the last tampon without shouting, "I'm using the last tampon!" (I'm totally guessing that this is even an issue, but I felt compelled to include it so the denizens of the women's locker room wouldn't feel excluded. I'm sensitive like that.)
Waste $40 million on a vulgar inauguration festival celebrating a painfully divisive election you barely won while people all over the world who are suffering and dying because of poverty, epic natural disasters and a war you lied us into starting could find a million more productive uses for that kind of money. Um … and wear little coordinated outfits when you work out.