She pissed off most of the staff. She introduced a weird iteration of "fire the bottom performers every year". She bailed out Dan Loeb (who had hired her but changed his mind after she refused to do almost anything she promised). She didn't get a particularly good price in the eventual sale. She got paid hundreds of millions for nothing (her pay alone was ~5% of the eventual sale price...one person). Terrible acquisitions. Terrible hires. She also appears to have rubbed almost everyone she met up the wrong way (I know people who met her and got a bad impression, imo she came across very poorly to investors and was preoccupied with perception/spin...I believe she gave an interview a few years ago in which she even blamed Carl Ichan...truly odd).

Most people are, I think, quite forgiving when it comes to failing in these situations. The issue often is that some people, most in my experience, have no idea how to behave when things go wrong (and, given enough time, something will always go wrong).