Do you live in New York or on or near the West Coast?
In my experience, I really feel like the place a person lives, and where their foundations are, has a lot to do with how others will react to them. Everywhere you go there will always be a Walmart and a McDonalds; but, people really are different, sometimes, from place to place..
It's queer. People used to gravitate towards me as you describe, where I used to live, in the Midwest; but, now, in the Western United States, I feel like a pariah. I'm well groomed, polite, non-confrontational... It isn't enough, people generally seem slightly unnerved by me (like they don't know what to make of me, except that I feel like an outsider to them), and consequently often hostile. It depends on the environment though, some places aren't as bad as others..
And believe me, from my perspective, it's much nicer when people generally respond positively to you. I suppose I was fortunate, in that, people usually left me alone, when people generally responded positively to me; but, even as of a few years ago, I'll still get the occasional person who just feels very talkative around me. It can be uncomfortable; but, it's a hell of a lot better than cashiers, and random people you've never met before, just acting like you're a leper or something, for no discernible reason.
I think our state of mind, in one form or another, or multiple ways, broadcasts itself, and people pick up on it; that, combined with our general personality, the things that went into it's formation, and the physical places we find ourselves in, pretty much sums up the lot of it. Our appearance and presentation has an effect, that, I surmise, will be different from place to place, circumstance to circumstance.
Like how a city slicker will generally find nothing but hostility out in the boonies; they'll be viewed as a fancy pants outsider. I guess sometimes we are just out of our element, literally, or in our mind, or both...
To the OP, so, I doubt very much you are a creep, and people probably don't really think that of you either. There's just a lot of factors that are in play. And unfortunately, when our confidence is low like that, and people in general often take offense to quiet types who try to avoid trivial social situations, it becomes a bit of a vicious circle. You feel like an outcast, so you sort of assume the role of outcast, covertly, and people begin to respond in ways that reinforce the belief that motivates your behaviors, and it just sort of feeds on itself.
I can remember times in my past though, where, I had known people, but not very well, only to find myself in a situation where we actually have a chance to truly get to know one another. And the person or persons say they thought I was this that and the other, and I say I thought you were this that and the other, and we were both totally wrong; and that we both weren't anything like what our preconceived notions were.
It's just that, especially when one feels like an outsider, you're going to avoid the types of situations that may lead to preconceived notions being dispelled.
So, we can't always give as much credit to the way we feel, as we often do. There are so many variables to consider; the chance that we have come to erroneous conclusions is quite high. And it's even higher in these times of confusion, despair, insanity, madness, and hostility; because, these are new and challenging times, the world over...
Just my 2 cents anyway.
And yeah, the single man syndrome, eh, it happens. Not much one can do about it. About the only thing you could do to improve it, is not obsessive over it constantly, and make it out to be worse than it is. It's tough being a single woman too, in different ways, and different people will experience it differently. For some, it works to their advantage, for others, they find it a curse. But, perception and the angle we come at the world, I think, has a lot more value to it, than what we often consider.
It's kind of the old question, "does the world out there, happen to you, or do you happen to it." And whatever the answer is, seems interesting to ponder, "why is that so?"
It's a bit of both, at different times... etc.. etc..