Oh Christ....here's mine....and don't mind the commentary....
Idiots who circuit train during busy times - These idiots need to realize that they don't own the equipment and that others are paying to use the equipment too.
Shadow boxers - These morons need to realize that they are in the wrong gym. There are plenty of martial arts dojo's and boxing academy's that can accomadate these goofs. Translation = "Hey everyone look at me...I can't dumbbell press 60 lbs but i'll show them what a tough guy I am by throwing hooks and uppercuts.

"
People who moan like elephants - You had better have at least 4 plates aside on that bar before you even make a peep. I know guys who barley make a sound deadlifting 6 plates aside. Translation = "Hey everyone, look at me...I just completed a set of dumbell curls with 40lbs

"
People who leave towels / bottles on equipment = if your not using it, put it elsewhere. You don't own it.
People who leave dumbbells all over the floor - No etiquette what so ever.
Women who use flat benches as stair climbers - Its not a fucking stair climber and your ruining the bench. Go to Bally's for that shit.
People who do push ups and chin ups - These people need to quit or get their head checked. You can do that shit at home in your cellar. It amazes me how with all the array of dumbbells and machines and hammer strengths how people still invent their own excersises. These of course are the same people who weight 165lbs in 2005 and in 2011 they still look the same and weight the same.
Self righteous naturals - These guys are the biggest joke of all. "I never take steroids and never will...drugs are bad! I saw on CNN!". Oh really? I suppose you refused your polio shots as well.

These guys take pride in gaining a half a pound a year. Then when they get a headache, they will go to the drug store and buy EXTRA STRENGTH advil and pop them like pez....but steroids are bad because the TV says so....wow...
Trainers who think they know it all - These idiots walk around like they own the place with their mind blowing 150lb physiques who took their 1 day certification test and now all of a sudden they are Charles Glass.
Steroid
abusers - These guys weigh 180lbs....two months later...they weigh 235lbs of water retention, no strength whatsoever and they think that qualifies them to wear tank tops, stringy tops, fag tops, etc. Two months later they are back to 180lbs, burnt receptors with sweaters in the gym hiding their pathetic 5000mg a week physique that withered away with the wind. These idiots also never heard of nutrition, dicipline, hard work or supplementation.
Tall guys 6ft plus that think they're "big" because they weight 225lbs - Your not big. At your height and weight you should be triple your size. Epic jealousy of these morons that blame their ZERO strength to "long limbs" WTF??? Bottom line, you can't lift the weight. Your weak as shit. Admit it and move on.
Older people with pot bellies that weight 160lbs but they're doing wrist curls on the one bench that you need and are waiting on - enough said.