It happens to me all the time. People at the gym annoying me with poor etiquette. There really are some simple things to remember when hitting the gym that will make everyone much happier.
1. Re-rack your weights. When you use something at the gym, be sure to put it back where it belongs. If you are done with your exercise, take the weights and put them back on the rack where they belong. If you took a bar from the rack put it back where you got it from. This will make it easier for the next person to find what they are looking for. If everyone adhered to this simple principle we would all be happier at the gym.
2. Let people work in. Yes, you may be doing a massive 5 sets on the squat rack, but that is no reason to hog the the thing. Let people work in. When you see someone standing waiting for your equipment offer to allow them to work in. If they refuse at least you made the offer. This will keep things moving. The gym will avoid a long line for the most popular equipment. At the same time, you may make a new friend.
3. Keep socializing to a minimum. There is nothing wrong with talking to your buddy while training, but keep it to a minimum. Don't hold up the equipment to have a discussion about that big football game last week. At the same time, avoid trying to pick up on women. It is the gym, not a night club.
4. Wipe off the equipment. Nobody wants to swim in your sweat. Take the time to wipe down the equipment before moving on. This includes cardio equipment.
5. Don't offer unsolicited advice. If someone asks your opinion on their lift by all means tell them, but don't just offer up your advice. Let the coaches coach and the lifters lift.
Remember these 5 simple things while at the gym and you will have a much better experience. Remember, humans tend to be followers, so anyone watching and observing you will likely follow suit and start doing these things as well.