Why do some men stare at me while I’m doing a workout?

Some women too. I’m not exceptionally big but sometimes when I’m doing arms guys will just stare at me while I’m doing my set. Like I said it’s not even big weight. It makes me nervous and they’ll just stop looking when I’m done, wondered if they’re judging my form but I got a professional opinion on my form and they’re STILL staring at me?

Why do some men stare at me while I’m doing a workout?
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