I'm at the gym and I'm looking at an attractive woman working out. Im at a distance but she still could see that I'm looking at her. I stare. I enjoy the view. I lust her. Then I break eye contact because I feel creepy.

However, judging by the way she glanced at me as she walked around the gym, she kind of liked it.

However, I still can't tell if I'm being creepy or good. What is the criteria to decide whether something is creeepy or cool and attractive? Is it the postive/negative reaction of the woman? Is just the act of lusting, on another person in a public space, or what?