Katie seems to develop obsessions about her bosses, which start off with her working somewhere, having an affair with them, breaking up their existing relationship, and then ending soon afterwards, with her going to work somewhere else.
This appears like an obvious pattern in her behaviour.
She also talks about the "many Katies" almost as if she has a split personality disorder. This is also obvious in the way she like to "imagine" herself as other people, for example Mavis or Jay.
She really is a very odd person.