I assumed the same, but I saw an episode a few years ago when stuck in a hotel and I still hated her character. Does not help that a lot of the story lines have their basis on a character doing something unknowing that it will cause the issue the story then has to solve, and then having her more then other characters fill the part of making things bad or worse.
I never thought her character was "bad" or "evil" and the actress did a great job most of the time. I just found her character insufferable most of the time. Actually most of the characters have points where they are insufferable, and that might in retrospect be why the show holds up.