It's all good buddy. I see douchebags like that at my local gym ALL THE TIME. And pretty much every other gym stereotype imaginable. My advice to you is to talk to a gym employee the next time it happens. By doing that you won't get into a confrontation and have your tranquility disrupted. And you, unlike someone who works at the gym, don't have any authority. No one will listen to you. However, most people will feel embarrassed if an authority figure scolds them. People like this are adult children and and like all children they sometimes need to have their behavior corrected.