1. Don’t leave your towel on one machine if you’re using another. Don’t claim a machine you’re not using.
2. Don’t leave your dirty clothes on the bench in the locker room. Use a locker.
3. Don’t flex in the mirror unless someone asks you to.
4. Scratch that: Don’t flex in the mirror, especially if someone asks you to.
5. Wipe down the machine.
6. Use a towel.
7. If you grunt under weight or pressure, learn to do it quietly.
8. Know where and how much you sweat. Dress accordingly. There’s nothing worse than a man with a soggy crotch wearing tight cotton shorts.
9. Don’t eat in the locker room.
10. Don’t spit in the drinking fountain.
11. Don’t impatiently ask someone how many more sets he has. And don't hover and glare. Go to another machine and wait your turn.