Sometime ago I came up with the formulation that "you're creepy" means "you're too focused on something that you want from me". It doesn't cover all the cases, but it gives a hint on how to avoid appearing creepy.
In the study, I'm glad that clowns are finally being called out!
One of the takeways is that the line between "cute flirting" and "creepy stalking" is if the other person is interested in you.
A flirter who flirts with me and makes it clear it's all in good fun, there's no pressure for more, if I need to go catch a bus I'm not an unfeeling b*^%$, if I don't feel like smiling/flirting it's ok; a flirter who makes me feel confident he's not going to call me names in public or follow me around for a week due to a pleasant interaction -- not creepy.
A flirter who keeps pressing on despite signs of discomfort, who doesn't leave me alone, who tries to imply I owe him something, who starts making grand plans for the future based on a few sentences interaction, who calls me names if I have to catch the bus -- creepy. These are all a little unpredictable (smiling conversation at a bar with a stranger, "Gotta go -- nice to chat!", sudden eruption of debasing language, for instance) as well as having high scores for other creepy factors identified in the paper.
A little test for yourself: flirt for enjoyment and then walk away with no expectation of ever talking to the person again. Can you do it? Practiced non-creepy flirters can do this well.
I'm a little wary of the term -- I think it's over deployed as a form of social violence -- but there's no denying that what you're describing happens and is pretty uncomfortable.
This may still be too general, as there are plenty of scenarios where this would connote "annoying" rather than "creepy," like with a persistent salesperson.
Perhaps it could be more accurate yet by adding "and I'm worried you may try to take it against my will, and have a chance of succeeding." to the end. That would cover, for example, noticing some masked figure sneaking toward your house with a crowbar.
EDIT: Although, I just realized I forgot to take out an unfinished sentence that was seemingly contradictory.
Example: in horror films, children can be super creepy, because there is a hint of supernatural threat. But in real life? Never, because they pose no threat.
Too focussed on something is only a symptom, the real feeling comes from fear that the individual is unstable or will go to extreme lengths to get what they seem to want. To avoid appearing creepy you need to understand what sort of fears people might have. The exact same interaction may be 10x creepier in an empty car park than a busy office floor. Sometimes the fears may be unwarranted or unfair, of course.
Another big class of creepy which works in both gender directions but because men are more threatening (for size if no other reason like testosterone) perhaps seems more one way is, "you seem or are desperate for friendship so you over interpret every little thing I do as a genuine or encouraging bond between us and you overdo your reactions"
But I'm not sure what else people might want that would fall into the same category. Salespeople, for instance, can seem "oily" but not usually creepy.
> It is our belief that creepiness is anxiety aroused by the ambiguity of whether there is something to fear or not
You mentioned:
> you're too focused on something you want, my ass and cleavage for instance
You can be focused on ass and cleavage, but not be creepy: eg, if you're honest and open that that's what you're looking for, and not trying to hide or be something you're not.
Creepiness occurs where that ambiguity exists: there's a discrepancy between someones evident intent and actions.
- If someone's trying to get you away from your friends, with a 'cool thing you need to see', but they clearly want to make out, it's creepy.
- If they say 'I think we should go somewhere and make out' it's less so.
A lot of creepiness comes from shy men who are afraid of rejection, other comes from shy men that understand, eg, that isolation makes people more likely to make out, but try and use subterfuge to make that happen.
I suppose that I believe the first part of your sentence, but I don't think that the second elaborates on it sufficiently. A guy who wore a sign saying "I am focussed on ass and cleavage!" and stared at those attributes of all women in the vicinity would, I think, still be creepy. (Maybe I am just using the word in a different sense.) I think that it is important to be open and honest about your intentions, but also to be willing to respect others' right to reject those intentions.
It is really hard to find a tank top that doesn't show cleavage if you are a certain shape. Tank tops are not always about a struggle for cute young men: these boobs are stuck to the front of me no matter what I'm thinking or doing, and their presence is not a sign of interest.
To assume otherwise causes creepiness.
edit: I'm legitimately asking. One of the things which stuck with me after reading "The Gift of Fear" is that people rarely get 'weird feelings' for no reason. If you're not interacting with somebody and they're still creeping you out, that's a sign that something is wrong. Pay attention to that feeling and get out of that situation, even if it means being rude.
Once you're out of that situation, you can certainly take time to think about "wait, why did that guy creep me out so much?". Maybe once you reflect on it, you'll say "He was way too fixated on that one woman struggling to put her groceries in the trunk of her car" or "He came up behind me on the stairs, but I never heard the door of the apartment building open after I came in, and that means he was probably waiting inside for me to pass him". Maybe you'll realize "oh, I was just being silly and there wasn't anything weird going on at all".
But think about it. What's the worst case scenario of paying attention to that feeling? You rudely brushed off somebody you don't know, didn't interact with, and will never see again. It's a bummer for them, and maybe they'll go home and tell their significant other a story about this one jerk they bumped into in the stairway today.
What's the worst case of ignoring that feeling because you don't want to be rude, or you think you're being unfair? The worst case is that you will get killed. The calculus on that is pretty easy for me.
There's also attractiveness as an input factor, at least if the person branding someone 'creepy' is shallow or superficial.