Women are constantly comparing themselves to other women (both real and airbrushed in media), because they know both men and women are comparing them to other women!!!!!!!! We are judging their asses, their boobs, and other women are even more judgemental than we are!! So of course women have insecurities.
Ya jokers at work hitting on them in a goofy way (customers) or the sad, pathetic coworker who won't give up are common examples too lol One girl was pretending to be annoyed by flaunting how this rich old geezer hits on her the other day. He doesn't have a chance in hell but she still enjoys the ego boost, and I think he gets some kind of kick out of flirting with her so it's not a bad thing. Another guy I know meets basically all his gfs at work, there is a high staff turnover there and he isn't big on approaching anyway.
One of the great myths perpetuated by PUA crap is that you have to do something special to get girls interested. The poor victim of such thinking walks around all day worrying about if he is holding his head at a perfect position, worried about if he says the exact right thing, worried about other guys and what they are doing, and often creates a situation twice as weird as just actually opening his mouth talking to someone about something that would make sense. I know of a guy who started taking classes to learn some chinese secret of how to hold his spine at a "perfect position" lol and I saw him once after this and he looked like someone shoved a huge dildo up his ass.