Harloys, the "All-knowing". In mage society, where knowledge was powerful, this nickname would not only attract a great deal of attention, it would also attract a great deal of hate.
All-knowing? Didn't this mean that she knew more than any other mage? Since mages were also scholars, this was like a mega taunt to all other mages. However, not only had Harloys solidly retained her nickname for thousands of years, she even had great personal success at the Cloud Tower, where archmages were plentiful. She successfully taught many outstanding students.
But if she really tried to intentionally teach wrong things and guide students down the wrong path in magic, she would quickly lose her reputation and even be exiled from the Mage Country.