Gym Etiquette (Getiquette?)

My post yesterday got me thinking about things which bug me, my pet peeves if you will, and sure enough today at the gym someone pointed one out for me. I think on a larger scale you can derive it as ignorance, or maybe even selfishness; singing while at the gym. As anyone who's been to a large generally knows, some people choose to wear their own headphones and listen to their own music. I have no problem with this at all. In fact, I too usually wear my own headphones for some "pump-up" music. However, I have a problem when someone wearing headphones decides to vocalize the song their currently listening to. Nobody else wants to hear your sorry attempt at singing your favorite song. It's rather annoying and, as stated previously, ignorant. While I'm working out I do not want to hear you sing. Furthermore, the guy singing at the gym yesterday wasn't singing the correct words. He was making up his own "remix" and it was atrocious. I hope this guy isn't a rapper or any other type of lyricist for his day job, or he's in need of a career change.