I find myself getting checked out by a random girl, about every couple weeks. For reference, I go to Uni so this is probably from sheer volume, not due to being super attractive or anything. I'm talking prolonged eye contact for 2-3 seconds or longer, open body language, and sometimes even a smile or smirk.

Usually I end up chickening out and not approaching, because I feel like I am ONLY approaching her because of the choosing signals, which is desparate, shallow, and opportunistic. In theory, if I were a truly desirable man, I wouldn't need to rely choosing signals, I could just talk to random women and enough of them will like it. If I had options, I would also not need to rely on choosing signals, because enough women would approach me, or I would meet them through hobbies, school, etc. Futhermore, from her perspective, it looks like I am pursuing whichever women are the easiest, not the ones I actually want, which I don't think is a good look.

I then spend too long trying to think of a situational conversation starter that avoids the topic that she was just giving the signals. And it is still scary because she still knows she was giving the signals, and therefore I still look like an opportunistic bottom-feeder. Then usually just when I finish drafting the opener and the first few replies, she leaves and I lose the opportunity.