I don't dislike her. I am voting for her.
I could see how somebody might not like her because of her extremely secretive nature. It's not just emails, it goes well beyond that. She first got a national reputation for extreme secrecy during her negotiations in her executive position as Healthcare czar, before it was called Healthcare czar, back in 1992 and 1993. But even prior to that, it extends back to her role in [Bill] Clinton's gubernatorial runs and her political involvement as Wellesley. Her friends have found she falls back to extreme secrecy. I also think she might have a borderline neurotic personality with a persecution complex, but I'm not sure how much of the evidence of that could be actually playing politics, or if she legitimately believed in things like "vast right wing conspiracies" in virtually every black mark against the Clinton administration. As somebody voting for her, I convince myself that it's her playing politics, but if I were on the fence about Clinton, then I could easily see it as being a neurotic persecution complex.
In both of these regards, she reminds me of Richard Nixon, and I'm not saying that a Clinton white house would be like a Nixonian white house -- it wouldn't be -- but it's a very easy comparison with these two personality flaws. Nixon's downfall was driven by an extreme desire for secrecy, which was fueled by a personality complex around feeling persecuted, and it bordered on dementia for him. Clinton's secrecy and persecution complex, at least from my perspective, don't rival Nixon's, but they are reminiscent of it.