There is one particular fellow who gets on a machine, does a few reps and then takes the longest rest between sets in history. When you ask if you can work in with him, he responds with something like, "I just have a couple more sets." This means he will be sitting there for the next 30 minutes. The guy is just plain rude. Fortunately, he isn't at the gym that often. I am a patient man, however after a few times of this I might have to say something not very nice to him, like, get the fuck off the machine or use it!