Like you said, it's a public gym. You should be willing to share with the public. It's poor etiquette to refuse. It's not like you're capable of exercising non-stop. So when you take a breather, let someone else use the equipment. Is that so hard?
Not everyone has more than an hour to work out. You should let people work in. I have no issue with it.
I've been working out for years off and on. Mostly Brazilian Jiu-jitsu, boxing, and thai boxing (10) years . Been lifting weights off and on for about 5 years. I usually knock out my sets pretty quick so I am off the machine so others can use it. How is that selfish? I just personally don't care for working out with strangers. That's all.
I also hate when the giant roided out body builder insist on wearing tights and shorter than John Stockton's basketball shorts. Body building gear is really weird and creepy man.
why wouldn't you let someone work in with you? that's just a dick move. your workout isn't going to be ruined because you shared one piece of the equipment you're going to use that day.
i do not take much time between sets, so it's an inconvenience to let someone work in. seeing that i do not let people work in, i don't ask others to let me work in. i simply do something else until the equipment i want is free to use. also, it's not my problem if someone has a time constraint. i lift for 45 minutes to 1.5 hrs. it's not like i live there. everybody needs to learn how to wait their turn, and not take 5 minutes between sets. i feel like those who ask to work in feel entitled because they are in a rush or whatever... and that's not polite. irks the crap out of me.
I ask to work in due to my routine, not because I think my time is worth more than anyone else's. No matter what body part I'm working, I do the heavier lifts first. i.e. I'm not doing fly's before bench.
in between 30 seconds and 2 minutes. i try not to take much time between sets to build muscle endurance.
what is the proper gym etiquette anyway when it comes to sharing I mean OP has 4 sets left, is that a lot for people to wait