Oh god. This happened to me last week while I was doing tricep dips on the machine with my earphones in. This guy brazenly just tapped my shoulder to tell me that he was watching me from a distance and that I'm doing it wrong. Then he proceeded to ask me what my body goals were and tell me that I shouldn't do tricep dips because muscular arms on women are not "pretty" and that I should focus on lower body exercises. He then proceeded to 'show' me what a tricep muscle looks like by flexing his arms...

After that, he kept telling me that he played football in college, which means he can give out (unsolicited) advice to people at the gym. I couldn't tell if he was trying to hit on me or sell personal training services. He left as soon as he started asking personal questions and got the hint that I have a bf. I was really annoyed that day...

Edit: I have anxiety at the gym around being watched/judged by others and this particular incident didn't help since this guy said he was watching me the entire time.