At the gym:
If you are relaxed enough to read your book or talk/text on your iphone for 30 minutes, then you should just go home.
Put your weights away after you use them, and put them away properly, are you a 2-year-old?
Obnoxious grunting, when not warranted by heavy weight or extreme exertion (and even in those cases, most of the time), make me want to jump-rope with your spine.
Do not drop or throw the weights, unless they are olympic weights or you are using a rubber platform. Be respectful of the equipment.
Don't hock a fucking nasty loogie of phlegm into the water fountain, you sick bastards.
Don't jack machines or weights from people until they are done, learn to work-in like an adult. Sharing is caring.
If you smell like a Wildebeast in heat, go home and take a shower plleeeeaaaase.
Girl in the very nice yoga pants, you rustle my jimmies in a very different way, please proceed...