"Oh no no, there's no else here but you. Take over!" and more passive-aggressive thoughts from a gym rat.
  1. Dropping heavy weights without regard to clanging, both in free- and machine-form.
    No no, that crazy clanging didn't bother us at all.
  2. Loud exclamations of any kind.
    UGHHHH! WOOO! YEAHHHHH! We want to grunt along with you. Louder, please!
  3. Leaving the windows open and the AC blazing.
    This really applies to apartment gyms... Oh please customize the temperature solely to your liking AND waste energy. We like that!
  4. Taking up a million pieces of equipment at once.
    Your 10-step circuit is way more important than our workouts. You do you!
  5. Lecherous stares.
    Subtly is def not something a lady appreciates. Look on!
  6. What did I miss, friends? I'm obviously needing a vent sesh, and I bet you do too! ;)
  7. Attempting conversation with someone wearing headphones on the treadmill next to you.
    Oh yes, random stranger, please tell me more about the tricks you taught your cat. I would much rather listen to that while I run than Beyoncé.
    Suggested by @gabimoskowitz
  8. Bringing a large Bluetooth stereo to your building's gym and blasting hip hop while everyone else politely wears headphones. (Note: I seriously love hip hop but this is just silly)