This isn't an attack or anything, but I really have a problem when people (almost entirely women in this case) label people who flirt with them as "creepy."
Granted, some people are a little bit inappropriate, especially whilst flirting, but more often than not people find it creepy when they don't find the person flirting with them attractive. Whilst these same people usually find similar behaviour from somebody who they do find attractive/or find charismatic as charming.
Another reason that I don't like the term creepy is it projects nefarious motives and potential aggression onto the guy (using "guy" here because it's almost entirely men who get labelled this way) for no other reason than he dared to try and win you someone over. For all you (collective you here) know the guy may not be the most confident, which is not only usually considered an unattractive quality but can lead to things like social awkwardness, which in turn can lead to anything he says coming across as a little off colour. When in fact he could have been plucking up the courage to just come over and say hi.
I just find it such a derogatory term to use as it's more often than not an emotional reaction disguised as character judgement. You see it all the time, charismatic, good looking people get away with things that others would get maced for. Whilst less attractive, socially inept people get labelled creepy for behaviour that is far more benign.
Point being, the act of flirting isn't creepy. I would bet that most people here met their girlfriends, boyfriends, husbands and wives through a little flirting.