It's where you start thinking you can't possibly be skilled and competent because if you were surely others would recognize it? And therefore the success you *do* have must be a fluke, because clearly your work isn't that good; other people work half as hard for more recognition.

So now we have a "women don't ask" situation, where we imagine that this behavior is just some odd quirk of self-esteem--women holding themselves back for no reason. When actually they are responding reasonably to the risks and challenges they face as women at work.

Women "don't ask" because they're far more likely to be retaliated against for asking. Women get impostor syndrome because people keep telling them that they're not as smart/skilled/talented as the men around them and that their achievements are worth less. It is systemic.